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FRICTION Level 1 Marked Questions can be used as Revision Questions. PART - I : SUBJECTIVE QUESTIONS Section (A) : Kinetic Friction A-1. Suppose you are running f...
FRICTION Level 1 Marked Questions can be used as Revision Questions. PART - I : SUBJECTIVE QUESTIONS Section (A) : Kinetic Friction A-1. Suppose you are running fast in a field. When you suddenly find a snake in front of you, you stop quickly. Which force is responsible for your deacceleration ? A-2.# In the given diagram find the direction of friction forces on each block and on the ground (Assume all surfaces are rough and all velocities are with respect to ground). A-3.# The wheel shown in the figure is fixed at ‘O’ and is in contact with a rough surface as shown. The wheel rotates with an angular velocity . What is the direction and nature of friction force on the wheel and on the ground. A-4.# In the following figure, find the direction of friction on the blocks and ground. A-5.# In the following figure, find the direction and nature of friction on the block. A-6. A block is shot with an initial velocity 5ms–1 on a rough horizontal plane. Find the distance covered by the block till it comes to rest. The coefficient of kinetic friction between the block and plane is 0.1. Section (B) : Static Friction B-1.# The person applies F force horizontally on the smaller block as shown in figure. The coefficient of static friction is between the blocks and the surface. Find the force exerted by the vertical wall on mass M. What is the value of action-reaction forces between m and M? B-2.# In the figure shown calculate the angle of friction. The block is just about to slide. Take g = 10 m/s2. B-3. What is the minimum value of force (in following two cases) required to pull a block of mass m on a horizontal surface having coefficient of friction ? Also find the angle this force makes with the horizontal. (a) If force is parallel to horizontal surface (b) If force is in any direction (Also find the angle this force makes with the horizontal.) Section (C) : Miscellaneous Questions C-1. A body of mass 5 kg is kept on a rough horizontal surface. It is found that the body does not slide if a horizontal force less than 30 N is applied to it. Also it is found that it takes 5 seconds to slide throughout the first 10 m if a horizontal force of 30 N is applied and the body is gently pushed to start the motion. Taking g= 10 m/s2, calculate the coefficients of static and kinetic friction between the block and the surface. C-2.# In the given figures find the accelerations and the friction forces involved : (i) (ii) (iii) (iv) PART - II : ONLY ONE OPTION CORRECT TYPE Section (A) : Kinetic Friction A-1. Starting from rest a body slides down a 45º inclined plane in twice the time it takes to slide down the same distance in the absence of friction. The co-efficient of friction between the body and the inclined plane is: (A) 0.75 (B) 0.33 (C) 0.25 (D) 0.80 A-2.# A wooden block of mass m resting on a rough horizontal table (coefficient of friction = ) is pulled by a force F as shown in figure. The acceleration of the block moving horizontally is : F cos F sin (A) (B) m M F (C) (cos + sin ) g (D) none of these m Section (B) : Static Friction B-1. If the normal force is doubled, the co-efficient of friction is : (A) halved (B) doubled (C) tripled (D) not changed B-2.# A box 'A' is lying on the horizontal floor of the compartment of a train running along horizontal rails from left to right. At time 't', it decelerates. Then the resultant contact force R by the floor on the box is given best by : (A) (B) (C) (D) B-3. A block of mass 1 kg lies on a horizontal surface in a truck. The coefficient of static friction between the block and the surface is 0.6 If the acceleration of the truck is 5 m/s2, the frictional force acting on the block is : (A) 5 N (B) 6 N (C) 10 N (D) 15 N B-4. A block of mass 2 kg rests on a rough inclined plane making an angle of 30 0 with the horizontal. The coefficient of static friction between the block and the plane is 0.7. The frictional force on the block is : (A) 9.8 N (B) 0.7 × 9.8 3 N (C) 9.8 × 7 N (D) 0.8 × 9.8 N B-5. Two masses A and B of 10 kg and 5 kg respectively are connected with a string passing over a frictionless pulley fixed at the corner of a table as shown. The coefficient of static friction of A with table is 0.2. The minimum mass of C that may be placed on A to prevent it from moving is (A) 15 kg (B) 10 kg (C) 5 kg (D) 12 kg Section (C) : Miscellaneous Questions C-1. A 60 kg body is pushed horizontally with just enough force to start it moving across a floor and the same force continues to act afterwards. The coefficient of static friction and sliding friction are 0.5 and 0.4 respectively. The acceleration of the body is : (A) 6 m/s2 (B) 4.9 m/s2 (C) 3.92 m/s2 (D) 1 m/s2 C-2.# A force F = t is applied to block A as shown in figure. The force is applied at t = 0 seconds when the system was at rest and string is just straight without tension. Which of the following graphs gives the friction force between B and horizontal surface as a function of time ‘t’. (A) (B) (C) (D) PART - III : MATCH THE COLUMN 1.# In the given figure find the accelerations of blocks A and B for the following cases (g = 10 m/s2) Column – I Column – II (A) 1 = 0 and 2 = 0.1 (p) a A = aB = 9.5 m/s2 (B) 2 = 0 and 1 = 0.1 (q) a A = 9 m/s2, aB = 10 m/s2 (C) 1 = 0.1 and 2 = 1.0 (r) aA = aB = g = 10 m/s2 (D) 1 = 1.0 and 2 = 0.1 (s) aA = 1, aB = 9 m/s2 2.# Column II gives certain situations involving two blocks of mass 2 kg and 4 kg. The 4 kg block lies on a smooth horizontal table. There is sufficient friction between both the blocks and there is no relative motion between the blocks in all situation. Horizontal forces act on one or both blocks as shown. Column I gives certain statement related to figures given in column II. Match the statements in column I with the figure in column II. Column I Column II 2kg 4kg 12N (A) Magnitude of frictional force is maximum. (p) 2kg 12N 4kg (B) Magnitude of friction force is least. (q) 2kg 6N 4kg 6N (C) Friction force on 2 kg block is towards right. (r) 8N 2kg 4kg 20N (D) Friction force on 2 kg block is towards left. (s) Level 2 Marked Questions may have for Revision Questions. PART - I : ONLY ONE OPTION CORRECT TYPE 1. A fixed wedge with both surface inclined at 45° to the horizontal as shown in the figure. A particle P of mass m is held on the smooth plane by a light string which passes over a smooth pulley A and attached to a particle Q of mass 3m which rests on the rough plane. The system is released from rest. Given that g the acceleration of each particle is of magnitude then 5 2 the tension in the string is : 6mg mg mg (A) mg (B) (C) (D) 5 2 2 4 2.# Starting from rest, A flat car is given a constant acceleration a0 = 2 m/s2. A cable is connected to a crate A of mass 50 kg as shown. Neglect the friction between floor and car wheels and mass of pulley. The cofficient of friction between crate & floor of the car is = 0.3. The tension in cable is - (A) 700 N (B) 350 N (C) 175 N (D) 0 3. A uniform rope lies on a table with some portion hanging. The rope begins to slide when the length of hanging part is 25 % of entire length. The co-efficient of friction between rope and table is: (A) 0.33 (B) 0.25 (C) 0.5 (D) 0.2 4#. In the arrangement shown mass of the block B and A are 2 m and, 8 m respectively. Surface between B and floor is smooth. The block B is connected to block C by means of a pulley. If the whole system is released then the minimum value of mass of the block C so that the block A remains stationary with respect to B is : (Co-efficient of friction between A and B is and pulley is ideal) m 2m 10 m 10m (A) (B) (C) (D) 1 1 1 5.# A block of mass m lying on a rough horizontal plane is acted upon by a horizontal force P and another force Q inclined at an angle to the vertical. The minimum value of coefficient of friction between the block and the surface for which the block will remain in equilibrium is: P Q sin Pcos Q P Qcos Psin Q (A) (B) (C) (D) mg Qcos mg Q sin mg Q sin mg Q cos 6. A bead of mass m is located on a parabolic wire (equation x 2 = ay) with its axis vertical and vertex directed downward as in figure. If the coefficient of friction is µ, the highest distance above the x-axis at which the particle will be in equilibrium is (A) µa (B) µ2a 1 1 (C) µ2a (D) µa 4 2 7. ˆ (with t A 1.5 kg box is initially at rest on a horizontal surface when at t = 0 a horizontal force F (1.8t)iN in seconds) is applied to the box. The acceleration of the box as a function of time t is given by : (g = 10m/s2) a0 for 0 t 2.85 ˆ a (1.2t 2.4)i m/s2 for t > 2.85 The coefficient of kinetic friction between the box and the surface is : (A) 0.12 (B) 0.24 (C) 0.36 (D) 0.48 8.# In the arrangement shown tension in the string connecting 4kg and 6kg masses is (A) 8N (B) 12N (C) 6N (D) 4N 9.# In the given figure the coefficient of friction between 4kg and 5 kg blocks is 0.2 and between 5 kg block and ground is 0.1. Choose the correct statements (A) Minimum force needed to cause system to move is 17 N (B) When force is 4N static friction at all surfaces is 4N to keep system at rest (C) Maximum acceleration of 4kg block is 2m/s2 (D) Slipping between 4kg and 5 kg blocks starts when F is > 17N 10.# Given m A = 30 kg, mB = 10 kg, mC = 20 kg. Between A and B friction coefficient 1 = 0.3, between B and C friction coefficient 2 = 0.2 and between C and ground 3 = 0.1. The least horizontal force F to start the motion of any part of the system of three blocks resting upon one another as shown in figure is (g = 10 m/s2) (A) 60 N (B) 90 N (C) 80 N (D) 150 N PART - II : SINGLE AND DOUBLE VALUE INTEGER TYPE 1. Two blocks A and B of equal masses are sliding down along straight parallel lines on an inclined plane of 45°. Their coefficients of kinetic friction are A = 0.2 and B = 0.3 respectively. At t = 0, both the blocks are at rest and block A is 2 meter behind block B. The time (in second) from the initial position where the front faces of the blocks come in line on the inclined plane as shown in figure. (Use g = 10 ms–2.) [JEE 2004 (Scr.) 3/84] A 2m B Fixed 45° 2. A block of mass 2 kg is pushed against a rough vertical wall with a force of 30 N, coefficient of static friction being 0.5. Another horizontal force of 15 N is applied on the block in a direction parallel to the wall. What is the acceleration of block (in m/s2) ? 3.# The rear side of a truck is open and a box of 40 kg mass is placed 5 m away from the open end as shown in figure. The coefficient of friction between the box and the surface below it is 0.15. On a straight road, the truck starts from rest and accelerates with 2 ms–2. Find the distance (in m) travelled by the truck by the time box falls from the truck. (Ignore the size of the box). 4.# In the given situation it is known that when released the blocks slide. Find the time (in second) when the small block will fall off from the larger block. (The size of m is very –very small then M, see figure). If m = 1 kg, M = 4 kg, = 4 m, = 37°, = 0.4. 5.# What is the maximum value of the force F (in newton) such that the block shown in the arrangement, does not move : [ JEE 2003 (Screening); 3/90] F 1 60º 2 3 m 3 kg /////////////////////////////////// 6.# In the figure shown, the coefficient of static friction between C and ground is 0.5, coefficient of static friction between A and B is 0.25, coefficient of static friction between B and C is zero. Find the minimum value of force ‘F’ (in newton), to cause sliding between A and B. Masses of A, B and C are respectively 2 kg, 4 kg and 5 kg. 7. A small body was launched up an inclined plane set at an angle = 15° against the horizontal. The coefficient of friction is k, if the time of the ascent of the body is = 2.0 times less than the time of its descent. Find value of 100 k PART - III : ONE OR MORE THAN ONE OPTIONS CORRECT TYPE 1. # A block of mass 15 kg is resting on a rough inclined plane as shown in figure. The block is tied up by a horizontal string which has a tension of 50 N. The coefficient of friction between the surfaces of contact may be (g = 10 m/s2) (A) 1/2 (B) 2/3 (C) 3/4 (D) 1/4 2.# Two masses m 1 = 4 kg and m2 = 2kg are connected with an inextensible, massless string that passes over a frictionless pulley and through a slit, as shown. The string is vertical on both sides and the string on the left is acted upon by a constant friction force 10 N by the slit as it moves. (Use g = 10 m/s2) SLIT 5 (A) Acceleration of mass m 1 is m/s2, downwards. 3 (B) Tension in the string is same throughout. 70 m1 4kg (C) Force exerted by the string on mass m 2 is N. 2kg m2 3 (D) If positions of both the masses are interchanged, then 2kg mass 10 moves up with an acceleration m/s2. 3 3. # Car is accelerating with acceleration = 20 m/s2. A box of mass m = 10 kg that is placed inside the car, it is put in contact with the vertical wall of car as shown. The friction coefficient between the box and the wall is = 0.6. (A) The acceleration of the box will be 20 m/sec2 (B) The friction force acting on the box will be 100 N (C) The contact force between the vertical wall and the box will be 100 5 N (D) The net contact force between the vertical wall and the box is only of electromagnetic in nature. 4.# A block of mass 1 kg is stationary with respect to a conveyer belt that is accelerating with 1 m/s2 upwards at an angle of 30º as shown in figure. Which of the following is/are correct? (A) Force of friction on block is 6 N upwards along the inclined plane. (B) Force of friction on block is 1.5 N upwards along the inclined plane. (C) Contact force between the block & belt is 10.5 N. (D) Contact force between the block & belt is 5 3 N. 5.# An arrangement of the masses and pulleys is shown in the figure. Strings connecting masses A and B with pulleys are horizontal and all pulleys and strings are light. Friction coefficient between the surface and the block B is 0.2 and between blocks A and B is 0.7. The system is released from rest. (use g = 10 m/s2) 6 kg A 3 kg B = 0.2 6kg Block C 1kg Block D (A) The magnitude of acceleration of the system is 2 m/s2 and there is no slipping between block A and block B. (B) The magnitude of friction force between block A and block B is 42 N. (C) Acceleration of block C is 1 m/s2 downwards. (D) Tension in the string connecting block B and block D is 12 N. PART - IV : COMPREHENSION Comprehension - 1 A block of mass 15 kg is placed over a frictionless horizontal surface. Another block of mass 10 kg is placed over it, that is connected with a light string passing over two pulleys fastened to the 15 kg block. A force F = 80 N is applied horizontally to the free end of the string. Friction coefficient between two blocks is 0.6. The portion of the string between 10 kg block and the upper pulley is horizontal as shown in figure Pulley string & connecting rods are massless. (Take g = 10 m/s2) 1. The magnitude of acceleration of the 10 kg block is : (A) 3.2 m/s2 (B) 2.0 m/s2 (C) 1.6 m/s2 (D) 0.8 m/s2 2. If applied force F = 120 N, then magnitude of acceleration of 15 kg block will be : (A) 8 m/s2 (B) 4 m/s2 (C) 3.2 m/s2 (D) 4.8 m/s2 3. Continuing with the situation, if the force F = 80 N is directed vertically as shown, the acceleration of the 10 kg block will be : (A) 2 m/s2, towards right (B) 2 m/s2, towards left (C) 6 m/s2, towards left (D) 16/5 m/s2, towards right Comprehension # 2 Impending state of motion is a critical border line between static and dynamic states of a body. A block of mass m is supported on a rough vertical wall by applying a force F as shown in figure. Coefficient of static friction between block and wall is S. The block under the influence of F sin may have a tendency to move upward or it may be assumed that F sin just prevents downward fall of the block. Read the above passage carefully and answer the following questions. 4. The minimum value of force F required to keep the block stationary is : mg mg mg mg (A) (B) (C) (D) cos sin cos sin cos tan 5. The value of F for which friction force between the block and the wall is zero. mg mg mg (A) mg (B) (C) (D) sin cos tan 6. If F is the force applied on the block as shown and F min is the minimum value of force required to keep the block stationary. Then choose the correct alternative. (A) If F < F min ; the block slides downward (B) If F = F min ; the block slides upward (C) In each case (for any value of F) the friction force f < mg (D) All the above Comprehension # 3 In the figure shown below the friction between the 4 kg block and the incline as 1 and between 8 kg and incline is 2. (Take g = 10 m/s2) m 1 =4 kg 1 m 2 =8 kg 2 30º ( 7. If 1 = 0.2 and 2 = 0.3 then find acceleration of m 1 and m 2 ? (A) a1 = a2 = 2.7 m/s2 (B) a1 = 3.2 m/s2, a2 = 2.4 m/s2 2 (C) a1 = a2 = 3.2 m/s (D) a1 = 2.4 m/s2, a2 = 3.2 m/s2 8. If 1 = 0.3 and 2 = 0.2 then find acceleration of m 1 and m 2 ? (A) a1 = a2 = 2.7 m/s2 (B) a1 = 3.2 m/s2, a2 = 2.4 m/s2 2 (C) a1 = a2 = 3.2 m/s (D) a1 = 2.4 m/s2, a2 = 3.2 m/s2 Comprehension # 4 MA = 3 kg, MB = 4 kg and MC = 8 kg. Friction cofficient between any two surfaces is 0.25. Pulley is frictionless and string is massless. Block, A is connected to the wall through a horizontal massless rigid rod as shown in figure. (g=10m/s2) 9. Find the value of F to keep C moving with constant speed (A) 60 N (B) 40 N (C) 80 N (D) 100 N 10. If F is 200 N then find acceleration of B (A) 5 m/s2 (B) 10 m/s2 (C) 4 m/s2 (D) zero Level –1 PART - II PART - I Section (A) A-1. (A) A-2. (C) Section (A) A-1. Frictional force, which is a type of Section (B) electromagnetic force. B-1. (D) B-2. (C) B-3. (A) B-4. (A) B-5. (A) A-2. Section (C) C-1. (D) C-2. (A) PART - III A-3. 1. (A) r, (B) q, (C) p , (D) s 2. (A) s (B) r (C) p, s (D) q, r Level –2 Kinetic friction is involved. PART - I A-4. 1. (B) 2. (B) 3. (A) 4. (D) 5. (A) 6. (C) A-5. Up the incline, kinetic friction. 7. (B) 8. (A) 9. (C) 10. (A) A-6. 12.5 m PART - II Section (B) 1. 2 2. 5 3. 20 B-1. action-reaction force between M and vertical 4. 2 5. 20 6. 15 wall 7. 16 N = 0 for F (M+m)g PART - III N= F– (M+m)g for F > (M+m)g 1. (A) (B) (C) 2. (A) (C) Action-reaction force between m and M 3. (A) (B) (C) (D) 4. (A) (C) 5. (A) (D) N = F – mg for F > mg and N = 0 for F < mg PART - IV 1. (A) 2. (B) 3. (A) B-2. = tan–1 4. (B) 5. (B) 6. (A) 2 7. (A) 8. (D) 9. (C) mg 10. (B) B-3. (a) mg (b) , tan–1 . 1 2 Section (C) C-1. s = 0.60, k = 0.52 C-2. (i) aA = 3 m/s2 , aB = 0 , f AB = 0 , f BG = 0 (ii) aA = 1 m/s2 , aB = 0 , fAB = 25N , f BG = 25N (iii) aA=5 m/s2 ; aB = 10 m/s2 ; f AB = 25N; fBG=75N (iv) aA= 1m/s2 ; aB = 1m/s2 ; f AB = 5N ; fBG = 75N 1 Class-11th JEE Chemical Bonding Octet Rule, limitations of octet rule,The Lewis Structures, Multiple Covalent Bonds, Ionic or Electrovalent Bonds, Formal charge 1. The sulphur compound in which the sulphur atom has (4) Small difference in electronegativity between octet configuration in its valence shell, among the the combining atoms. following is 9. The electronegativity of an element is low. The bond (1) Sulphur trioxide formed between two identical atoms of the above (2) Sulphur hexafluoride element is most likely to be (3) Sulphur dichloride (1) covalent (2) metallic (4) Sulphur dioxide (3) ionic (4) co-ordinate covalent 2. In which one of the following compounds does the 10. An element has 8 electrons in the valence shell. central atom obey the octet rule? Which of the following is correct? (1) XeF4 (2) XeOF2 (1) It will lose electron. (3) SCl2 (4) AlCl3 (2) It will gain an electron. (3) It neither gains nor loses electron. 3. The attractive force which holds various constituents (4) It will make bond with itself. together in different chemical species is called (1) valence bond (2) chemical bond (3) atomic bond (4) electrovalent bond 11. The electronegativity of element helps in predicting (1) strength of the element 4. The octet rule is observed in (2) polarity of the molecule (1) PCl5 (2) CO2 (3) size of the molecule (3) BCl3 (4) SF6 (4) valency of the element. 5. Which of the following is electron-deficient? 12. The type of bonds present in CuSO4.5H2O_______. (1) (BH3)2 (2) PH3 (1) electrovalent and covalent (3) (CH3)2 (4) (SiH3)2 (2) electrovalent and coordinate (3) electrovalent, covalent and coordinate 6. The nature of bonding between adjacent atoms in (4) covalent and coordinate graphite is (1) covalent (2) ionic 13. Which of the following is correct for the process of (3) van der Waals (4) metallic formation of a chemical bond? (1) Electron-electron repulsion becomes more 7. Which one of the following contains ionic, covalent than the nucleus-electron attraction. and co-ordinate bonds? (2) Energy of the system does not change. (1) NaOH (2) NaCl (3) Energy increases. (3) HCl (4) NaNC (4) Energy decreases. 8. Which of the following is not a characteristic of a 14. The compound containing coordinate bond is covalent compound? (1) SO3 (2) O3 (1) Low melting point (3) H2SO2 (4) all of these (2) No definite geometry (3) Insoluble in polar solvent 2 15. If stability were attained with 6 electrons rather than with 8 electrons, what would be the formula of the 23. Molecule having an incomplete octet in the central atom stable fluoride ion is (1) F3+ (2) F+ (1) PCl5 (2) NH3 (3) F– (4) F2– (3) BCl3 (4) H2O 16. Duplet configuration is not found in 24. Octet rule is mostly violated in the compounds (1) Hydride ion (2) Hydrogen molecule formed by (3) Lithium cation (4) Be3+ (1) Alkali metals (2) Alkaline earth metals 17. The element having highest valency with respect to (3) p-block elements oxygen is (4) Transition elements (1) Sodium (2) Aluminium (3) Chlorine (4) Sulphur 25. NaCl does not exhibit space isomerism due to (1) Presence of ions 18. The electrons generally involved in bonding (2) High melting point (1) Are those that lie closest to the nucleus (3) Strong electrostatic forces between the (2) Are those for which the ionization energies are constituent ions small (4) Non directional nature of electrovalent bond. (3) Belongs to inner shells (4) Are free electrons 26. In PO34 , the formal charge on each oxygen atom and the P-O bond order respectively are 19. According to Fajans rule covalent bond is favoured (1) –0.75, 0.6 (2) –0.75, 1.0 by (3) –0.75, 1.25 (4) –3, 1.25 (1) Small cation and large anion (2) Small cation and small anion 27. RQ. (19) (3) Large cation and large anion (4) Large cation and small anion 28. RQ. (20) 20. Polarisation is the distortion of the shape of anion by 29. RQ. (21) an adjacently placed cation. Which of the following statement is correct? 30. The correct order of decreasing polarity is (1) Maximum polarization is brought about by (1) HF > SO2 > H2O > NH3 cation of high charge (2) HF > H2O > SO2 > NH3 (2) Maximum polarization is brought about by (3) HF > NH3 > SO2 > H2O cation of Low charge (4) H2O > NH3 > SO2 > HF (3) A large cation is likely to bring about a large 31. In which of the following molecules octet rule is not degree of polarization followed? (4) A small anion is likely undergo a large degree (1) NH3 (2) CH4 of polarization (3) CO2 (4) NO 21. Polarization power of a cation increases when 32. In a covalent bond formation, (1) Charge on the cation increases (2) Size of the cation increases (1) transfer of electrons takes place (3) Charge on the cation decreases (2) equal sharing of electrons between two atoms (4) Has no relation to its size or charge takes place (3) electrons are shared by one atom only 22. Example of super octet molecule is: (4) electrons are donated by one atom and shared by (1) ClF3 (2) PCl5 both atoms. (3) IF7 (4) All 3 33. Which of the following shows the Lewis dot formula (1) Energy is absorbed for CO2? (2) Forces of attraction overcome forces of (1) :O::C::O: (2) :O:C::O: repulsion (3) Forces of repulsion overcome forces of (3) :O:C:O: (4) :O:C:O: attraction 34. Among the following the exceptions of the octet rule (4) Forces of attraction are equal to forces of is repulsion (1) the incomplete octet of central atom (2) an odd number of electrons on central atom 40. Which of the following is an example of super octet (3) expanded octet of the central atom molecule? (4) all of these (1) ClF3 (2) PCl5 35. In which of the following species the bond is non- (3) IF7 directional? (4) All the three (1) NCl3 (2) RbCl (3) BeCl2 (4) BCl3 41. In an ionic compound A+ X– the degree of covalent bonding is greatest when: 36. Sodium chloride has a crystalline structure made up (1) A+ and X– ion are small of Na+ and Cl– ions. Why does NaCl not conduct (2) A+ and X– ion are large electricity in solid state? (3) A+ and X– ion are approximately of the same (1) The ions of NaCl become mobile only in size molten state and are not free to move in solid (4) A+ is small and X– is large state (2) The crystalline structure does not have ions 42. The most covalent halide of s-Block is (3) When a bond is formed between ions they lose (1) CsF (2) CsBr their charges (3) BeI2 (4) BeF2 (4) None of these 43. The maximum covalency of representative elements 37. Most ionic compounds have is equal to (excluding 1st and 2nd period) (a) high melting point and low boiling point (1) the number of unpaired p-electrons (b) high melting point and non-directional bonds (2) the number of paired d-electrons (c) high solubilities in polar solvents and low (3) the number of paired s and p-electrons solubilities in non-polar solvents (4) the actual number of s and p-electrons in the (d) three dimensional network structures and are outermost shell good conductors of electricity in the molten state 44. Which of the following contains both electrovalent (1) None of the above and covalent bonds? (2) b, c, d (1) MgCl2 (2) H2O (3) a, b, c (3) NH4Cl (4) None (4) All of the above 45. The types of bond present in N2O5 are (1) only covalent 38. Which of the following does not conduct electricity. (2) only ionic (1) Molten NaOH (2) Molten KOH (3) ionic and covalent (3) Solid NaCl (4) Aqueous NaCl (4) covalent and coordinate 39. Chemical bond formation takes place when 4 46. Example of super octet molecule is.. (3) ·X: (1) SF6 (2) PCl5.. (3) IF7 (4) ·: X : ·· (4) All of these 47. The number of electrons involved in the bond formation in N2 molecule is 55. Which of the following Lewis diagram is incorrect? (1) 2 (2) 4 (3) 10 (4) 6 (1) (2) 48. The octet rule is not obeyed in (1) CO2 (2) BCl3 (3) PCl5 (4) (2) and (3) both (3) (4) 49. For the formation of covalent bond the difference in 56. What are the formal charges on central sulphur and the value of electronegativity should be each terminal oxygen atoms in SO2? (1) 1.7 (1) 0, 0, 0 (2) + 2, 0, – 1 (2) More than 1.7 (3) 0, – 1, + 1 (4) + 2, + 2, + 2 (3) 1.7 or more (4) equal to or less than 1.7 57. Which of the following compounds does not follow the octet rule for electron distribution 50. NH3 and BF3 combine readily because of the (1) PCl5 (2) PCl3 formation of (3) H2O (4) PH3 (1) a covalent bond (2) a hydrogen bond 58. The valency of A = 3 and B = 2, then the compound is (3) a coordinate bond (1) A2B3 (2) A3B2 (4) an ionic bond (3) A3B3 (4) A2B2 51. The covalency of nitrogen in HNO3 is 59. Which of the following does not represent the correct (1) 0 (2) 3 Lewis structure for the compounds given? (3) 4 (4) 5 (1) MgO – [Mg]2+ ]2– 52. Which one of the following molecules has a co- (2) CN : C :::: N : ordinate as well as covalent bond? (3) BrF3 (Br in center) – (1) NH4Cl (2) AlCl3 (3) NaCl (4) Cl2 (4) All of these 53. Which of the following species are hypervalent ? 60. What are the formal charges on B and N respectively 1. ClO4– 2. BF3 2– in the given structure? 3. SO4 4. CO32– (1) 1, 2, 3 (2) 1, 3 (3) 3, 4 (4) 1, 2 54. If the atomic number of element X is 7 the Lewis diagram for the element is (1) X.. (2) ·X: (1) –1, + 1 (2) + 1, – 1.. (3) – 2, + 2 (4) 0, 0 5 61. What is the formal charge on N in 62. The bonds present in N2O5 are: (1) Only ionic ? (2) Covalent & coordinate (3) Only covalent (1) +1 (2) –1 (4) Covalent & ionic (3) 0 (4) +2 63. The pair of compounds which can form a co-ordinate bond is: (1) (C2H5)3 B and (CH3)3N (2) HCl and HBr (3) BF3 and NH3 (4) (1) and (3) both 6 64. In which compound coordinate bond is present: (1) LiCl < BeCl2 > BCl3 > CCl4 (1) NH3 (2) LiCl > BeCl2 < BCl3 < CCl4 (2) NH4OH (3) LiCl < BeCl2 < BCl3 < CCl4 (3) H2O (4) LiCl > BeCl2 > BCl3 > CCl4 (4) HCl 65. Among LiCl, BeCl2, BCl3 and CCl4, the covalent bond character follows the order – Ionic Bond: Factors which favour the formation of ionic bond, Lattice Enthalpy, Hydration Energy, Solubility of Ionic Salt, Thermal Stability 66. CaO and NaCl have the same crystal structure and 71. Number of electrons transferred from one atom to approximately the same ionic radii. If U is the lattice another during bond formation in SrS (Strontium energy of NaCl, the approximate lattice energy of Sulphide) CaO is (1) 1 (2) 2 (1) U/2 (2) U (3) 3 (4) 4 (3) 2U (4) 4U 72. Which of the following has the lowest Lattice energy? 67. During bond formation, potential energy of the (1) LiF (2) LiCl system (3) LiBr (4) LiI (1) Increases (2) Decreases 73. RQ. (68) (3) Remains the same 74. RQ. (69) (4) Cannot be predicted 75. RQ. (70) 68. Which of the following is not an ionic compound (1) CaC2 76. Sublimation energy of Ca is 121 kJ mol–1. Also (2) NaH dissociation energy of Cl2 is 242.8 kJ mol–1, total (3) BaF2 ionization energy of Ca(g) Ca2+(g) is 2422 kJ (4) BF3 and electron gain enthalpy of Cl is –355 kJ; lattice energy of CaCl2 is –2430.5 kJ. The value of H for 69. Which of the following is not a correct statement the following process Ca(s) + Cl2(g) CaCl2(s) about an ionic compound is__________(in kJ mol–1). (1) The higher the temperature, the more the (1) –355 kJ mol–1 (2) 355 kJ mol–1 solubility. (3) –355 J mol –1 (4) 355 J mol–1 (2) The higher the dielectric constant of the 77. Which one of the following has the highest lattice solvent, the more the solubility. energy? (3) The higher the dipole moment of the solvent, (1) LiCl (2) CaCl2 the more the solubility. (3) LiF (4) KCl (4) The higher the lattice energy, the more the solubility. 78. Amongst LiCl, RbCl, BeCl2 and MgCl2, the 70. Lattice energy depends on compounds with the greatest and the least ionic (1) Only radius of cation character respectively are: (2) Only radius of anion (1) LiCl and RbCl (3) Cation to anion radius ratio (2) RbCl and BeCl2 (4) Sum of the radii of cation and anion (3) RbCl and MgCl2 (4) MgCl2 and BeCl2 7 (2) Cl– > F– > Br– > I– 79. Lattice energy of a solid increases if (3) Br– > Cl– > F– > I– (1) The radii of ions are small (4) I– > Br– > Cl– > F– (2) The ions are neutral 86. Which is the Most soluble sulphate in water among (3) Charges on the ions are small the following compounds: (4) Madelung constant decreases (1) BaSO4 (2) SrSO4 (3) MgSO4 (4) BeSO4 80. The solubility of Na2SO4, BeSO4, MgSO4 and BaSO4 will follow the order 87. The ionic compounds will be sparingly soluble if. (1) BeSO4 > MgSO4 > Na2SO4 > BaSO4 (1) Hydration energy = lattice energy (2) BeSO4 > Na2SO4 > MgSO4 > BaSO4 (3) MgSO4 > BeSO4 > Na2SO4 > BaSO4 (2) Hydration energy > lattice energy (4) Na2SO4 > BeSO4 > MgSO4 > BaSO4 (3) Hydration energy < lattice energy (4) Hydration energy = 0 81. The decreasing order of ionic nature of the following compound is: 88. The solubility of KCl is relatively more in: (1) LiI > NaBr > KCl > CsF (1) C6H6 (Dielectric constant = 0) (2) LiI > KCl > NaBr > CsF (2) (CH3)2CO (Dielectric constant = 2) (3) CsF > NaBr > KCl > LiI (3) CH3OH (Dielectric constant = 32) (4) CsF > KCl > NaBr > LiI (4) CCl4 (Dielectric constant = 0) 82. Which of the following is correct order of solubility 89. Lattice energy of an ionic compound depends upon: (1) LiOH < NaOH < KOH < RbOH < CsOH (1) Charge on the ions only (2) LiOH > NaOH > KOH > RbOH > CsOH (2) Size of the ions only (3) NaOH < KOH < RbOH < CsOH < LiOH (3) Packing of the ions only (4) CsOH < NaOH < KOH < RbOH < LiOH (4) Charge and size of the ions 83. The most covalent halide of s-Block is 90. The correct order of decreasing polarizability of ion (1) CsF (2) CsBr is: (3) BeI2 (4) BeF2 (1) Cl– > Br– > I– > F– (2) F– > I– > Br– > Cl– (3) I– > Br– > Cl– > F– (4) F– > Cl– > Br– > I– 84. Correct order of melting point (ºC) of the following compound: NaBr, MgBr, AlBr3 91. Which ion has a higher polarizing power? (1) 91.5, 700, 755 (2) 755, 700. 91.5 (1) Mg2+ (2) Al3+ (3) 700, 755, 91.5 (4) 755, 91.5, 700 (3) Ca2+ (4) Na+ 85. The correct order of polarizability of X– is: (1) F– > Cl– > Br– > I– 8 Bond Parameter: Bond Length, Bond Angle, Bond Enthalpy 92. Most energetic species among the following is 99. The correct arrangement of the species in the (1) H2 (2) Ne decreasing order of the bond length between carbon (3) F (4) F2 and oxygen in them is (1) CO,CO2 , HCO2 ,CO32 93. The species, having bond angles of 120° is (2) CO2 , HCO2 ,CO,CO32 (1) CIF3 (2) NCl3 (3) CO32 , HCO 2 ,CO 2 ,CO (3) BCl3 (4) PH3 (4) CO,CO32 ,CO 2 , HCO2 94. Consider the molecules CH4, NH3 and H2O. Which of the given statements is false? 100. The correct order towards bond angle is (1) Bond angle does not depend on hybridization (1) The H—O—H bond angle in H2O is smaller than the H—N—H bond angle in NH3. (2) sp sp 2 sp3 (2) The H—C—H bond angle in CH4 is larger than (3) sp 2 sp sp3 the H—N—H bond angle in NH3. (4) sp 3 sp 2 sp (3) The H—C—H bond angle in CH4, the H—N— H bond angle in NH3, and the H—O—H bond 101. Which of the following has been arranged in angle in H2O are all greater than 90°. increasing order of % p-character? (4) The H—O—H bond angle in H2O is larger than (1) sp sp 2 sp3 (2) sp 3 sp 2 sp the H—C—H bond angle in CH4. (3) sp 2 sp 3 sp (4) sp 2 sp sp3 95. Which of the following has higher bond angle? (1) H2O 102. Which of the following compounds have bond angle (2) CH4 as nearly 90º? (3) Graphite (1) CH4 (2) CO2 (3) H2O (4) SF6 (4) SO2 103. The bond angle in ethylene is 96. In BF3, the B—F bond length is 1.30 Å, when BF3 is (1) 180° (2) 120° allowed to be treated with Me3N, it forms an adduct, (3) 109° (4) 90° Me3N→ BF3, the bond length of B—F in the adduct is 104. In which molecule are all atoms coplanar (1) Greater than 1.30 Å (1) CH4 (2) BF3 (2) Smaller than 1.30 Å (3) PF3 (4) NH3 (3) Equal to 1.30 Å (4) None of these. 105. Which has the least bond angle (1) NH3 (2) BeF2 97. The molecule having smallest bond angle is (3) H2O (4) CH4 (1) AsCl3 (2) SbCl3 (3) PCl3 (4) NCl3 106. In compound X, all the bond angles are exactly 109°28’, X is 98. Decreasing order of bond angle is (1) Chloromethane (1) BeCl2 > NO2 > SO2 (2) Iodoform (2) BeCl2 > SO2 > NO2 (3) Carbon tetrachloride (3) SO2 > BeCl2 > NO2 (4) Chloroform (4) SO2 > NO2 > BeCl2 9 107. Which of the following molecules has one lone pair 115. Which of the following statement is incorrect of electrons on the central atom regarding the structure of XeO2F2 molecule (1) H2O (2) NH3 (1) Xe = O bonds are present in axial position (3) CH4 (4) PCl5 (2) All Xe—F bond lengths are identical (3) FXeF angles are 90° 108. Select the correct order of H—M—H bond angle (4) Shape of the molecule is octahedral (1) PH3 PH 4 (2) P2 H 4 PH 4 116. Comment on the C—C bond length for C2H6 and C2F6 (3) PH 3 NH 4 (4) PH 4 NH 3 compounds 109. Compare bond angle x and y in the following (1) dC–C(C2H6) > dC–C(C2F6) molecules (2) dC–C(C2F6) > dC–C(C2H6) (3) dC–C(C2F6) > dC–C(C2H6) (4) Can’t be predicted 117. The correct order of ‘S – O’ bond length is: (1) SO32 SO42 SO3 SO2 (1) x>y (2) y>x (2) SO32 SO42 SO2 SO3 (3) x=y (4) None of these (3) SO24 SO32 SO2 SO3 SO24 SO32 SO3 SO 2 110. Find the number of 90° angles in XeF5 molecules (4) (1) 1 (2) 2 118. FAsF bond angle in AsF3Cl2 molecule is: (3) 0 (4) 3 (1) 90° and 180° (2) 120° (3) 90° (4) 180° 111. Find out the relation between (adjacent angle) FClF and FBrF bond angle in ClF3 and BrF3 119. The correct order of bond angles is : molecule respectively. (1) NO 2 NO 2 NO 2 (1) FClF > FBrF (2) FClF= FBrF (2) NO 2 NO 2 NO 2 (3) FClF < FBrF (4) Can’t predicted (3) NO 2 NO 2 NO 2 (4) NO 2 NO 2 NO 2 112. Which one correct for bond angle (1) PF3 < PCl3 (2) PF3 < PH3 120. The correct order of H – M – H bonds angle is (3) BF3 < BCl3 (4) All of these (1) NH3 < PH3 < SbH3 < BiH3 (2) AsH3 < SbH3 < PH3 < NH3 113. The correct order of dC−H in the following option is (3) NH3 < PH3 < BiH3 < SbH3 (1) CHF3 = CH2F2 = CH3F (4) BiH3 < SbH3 < AsH3 < PH3 (2) CHF3 > CH2F2 > CH3F (3) CH2F2 > CH3F > CHF3 121. The compound MX4 is tetrahedral. The number of (4) CH3F > CH2F2 > CHF3 XMX angles in the compound is: (1) three (2) four 114. O2F2 is an unstable yellow orange solid and H2O2 is a (3) five (4) six colourless liquid, both have O–O bond. O–O bond length in H2O2 and O2F2 is respectively 122. Which of the following set contains species having (1) 1.22 Å, 1.48 Å (2) 1.48 Å, 1.22 Å same angle around the central atom? (1) SF4, CH4, NH3 (3) 1.22 Å, 1.22 Å (4) 1.48 Å, 1.48 Å (2) NF3, BCl3, NH3 (3) BF3, NF3, AlCl3 (4) BF3, BCl3, BBr3 10 123. In which of the following molecules/ions all the 124. The correct order of bond angles (smallest first) in bonds not equal? H2S, NH3, BF3 and SiH4 is (1) SF4 (2) SiF4 (1) H2S < SiH4 < NH3 < BF3 (3) XeF4 (4) BF4 (2) H2S < NH3 < BF3 < SiH4 (3) H2S < NH3 < SiH4 < BF3 (4) NH3 < H2S < SiH4 < BF3 Resonating Structures, Dipole Moment 125. Which of the following molecules has the maximum 131. Identify the molecule that has zero dipole moment. dipole moment? (1) CH3Cl (2) CHCl3 (1) CO2 (2) CH4 (3) CH2Cl2 (4) CCl4 (3) NH3 (4) NF3 X 126. Pick up the incorrect statement. 132. Dipole moment of in 1.5D. The dipole (1) Dipole moment of ammonia is due to orbital dipole and resultant dipole in the same direction. (2) In BF3 bond dipoles are higher but dipole moment is zero. moment of is: (3) Dipole moment is a vector quantity. (4) O2, H2 show bond dipole due to polarisation. (1) 1.5 D (2) 2.25 D 127. Which of the following is the correct order of dipole (3) 1D (4) 3D moment? (1) NH3 < BF3 < NF3 < H2O 133. The bond length of HCl molecule is 1.275 Å and its (2) BF3 < NF3 < NH3 < H2O dipole moment is 1.03 D. The ionic character of the (3) BF3 < NH3 < NF3 < H2O molecule (in percent) (charge of the electron= 4.8 × (4) H2O < NF3 < NH3 < BF3 10–10 esu) is 128. Among the following molecules, which has the zero- (1) 100 (2) 67.3 dipole moment'? (3) 33.66 (4) 16.83 (1) BF3 (2) H2O (3) NF3 (4) ClO2 134. Consider the following halogen containing compounds 129. Which one of the following has the lowest dipole (a) CHCl moment? (b) CCl4 (1) CH3F (2) CH3Cl (c) CH2Cl2 (3) CH3l (4) CH3Br (d) Cl Cl 130. The dipole moment is minimum in The compounds with a net zero dipole moment are (1) NH3 (1) b and d only (2) NF3 (2) c only (3) SO2 (3) c and d only (4) BF3 (4) a and d only 11 135. If H − X bond length is 2.00 Å and H − X bond has 142. The bond angle and dipole moment of water dipole moment 5.12 × 10–30 C − m, the percentage of respectively, are ionic character in the molecule will be (1) 109.5°, 1.84 D (1) 10% (2) 16% (2) 107.5°, 1.56 D (3) 18% (4) 20% (3) 104.5°, 1.84 D (4) 102.5°, 1.56 D 136. The dipole moment of HBr is 1.6 × 10–30 C.m and inter – atomic spacing is 1 Å. The % ionic character 143. In a polar molecule, the ionic charge is of HBr is 4.8 × 10–10 e.s.u. If the inter ionic distance is 1 Å unit, (1) 7 (2) 10 then the dipole moment is (3) 15 (4) 27 (1) 41.8 debye (2) 4.18 debye (3) 4.8 debye (4) 0.48 debye 137. If the bond length and dipole moment of a diatomic molecule are 1.25 Å and 1.0 D respectively, what is 144. The electronegativity of A and B are 1.20 and 4.0 the per cent ionic character of the bond? respectively. Therefore, ionic character in A − B bond (1) 10.66 (2) 12.33 will be (3) 16.66 (4) 19.33 (1) 50% (2) 43% (3) 53.3% (4) 72.23% 138. Which of the following will have large dipole moment? 145. If the dipole moment of toluene and nitrobenzene are NH2 NO2 0.43 D and 3.93 D, then what is the expected dipole moment of p-nitro toluene? (1) 3.50 D (2) 2.18 D (1) (2) (3) 4.36 D (4) 5.30 D NH2 NH2 146. Which of the following has dipole moment? (1) CO2 (2) p-dichlorobenzene (3) NH3 (4) CH4 (3) (4) NO2 147. The only molecule having dipole moment is NO2 (1) CCl4 (2) NH3 (3) CF4 (4) BF3 139. Zero dipole moment is possessed by (1) PCl3 (2) BF3 148. Select the structures which have a permanent (3) ClF3 (4) NH3 dipole moment? OH O H 140. Which one of the following is a non-polar molecule? (1) CCl4 (2) CHCl3 (1) (2) (3) CH2Cl2 (4) CH3Cl 141. Identify the non-polar molecule in the set of O H compounds given Cl HCl, HF, H2, HBr (1) H2 (2) HCl (3) (4) All of these (3) HF, HBr (4) HBr 12 149. The order of polarity of NH3, NF3 and BF3 is 156. The correct order of dipole moment (1) NF3 < NH3 < BF3 (2) BF3 < NF3 < NH3 (1) CH4 < NF3 < NH3 < H2O (3) BF3 < NH3 < NF3 (4) NF3 < BF3 < NH3 (2) NF3 < CH4 < NH3 < H2O (3) NH3 < NF3 < CH4 < H2O 150. The decreasing order of dipole moment of molecules (4) H2O < NH3 < NF3 < CH4 is (1) NF3 NH3 H2O 157. Which of the following pair of molecules will have (2) NH3 NF3 H2O permanent dipole moment? (3) H2O > NH3 NF3 (1) NO2 and CO2 (2) NO2 and O3 (3) SiF4 and CO2 (4) SiF4 and NO2 (4) H2O > NF3 NH3 158. In which of the following molecule (observed) is 151. Which of the following molecules will have polar found to be greater than (theoretical): bonds but zero dipole moment? (1) O2 (2) CHCl3 (3) CF4 (4) None of these (1) (2) 152. Which has maximum dipole moment? (3) (4) None of these (1) (2) 159. Arrange the following compounds in increasing order of dipole moments, toluene (I), o-dichlorobenzene (II), m-dichlorobenzene (III) and p-dichlorobenzene (IV): (3) (4) (1) IV < I < II < III (2) I < IV < II < III (3) IV < I < III < II (4) IV < II < I < III 160. Which one of the following statements is true? 153. Correct set of species with zero dipole moment is: (1) The dipole moment of NF3 is zero. (i) CO2 (ii) COCl2 (2) The dipole moment of NF3 is less than NH3. (iii) CH2Cl2 (iv) BCl3 (3) The dipole moment of NF3 is more than NH3. (1) (i) and (iv) (2) (ii) and (iv) (4) The dipole moment of NH3 is zero. (3) (iii) and (iv) (4) (i), (iii) and (iv) 161. The dipole moment is the highest for 154. H2O has a net dipole moment while BeF2 has zero (1) trans-2-Butene dipole moment because: (2) 1, 3-Dimethylbenzene (1) F is more electronegativity than oxygen (3) Acetophenone (2) Be is more electronegativity than oxygen (4) Ethanol (3) H2O molecule is linear and BeF2 is bent (4) BeF2 molecule is linear and H2O is bent 162. If a molecule MX3 has zero dipole moment the sigma bonding orbitals used by M (atomic number 155. The dipole moment of HCl is 1.03D, if H–Cl bond < 21) are distance is 1.26 Å, what is the percentage of ionic (1) Pure p character in the H—Cl bond? (2) sp hybrid (1) 60% (2) 39% (3) sp2 hybrid (3) 29% (4) 17% (4) sp3 hybrid 13 163. Which of the following arrangement of molecules is 172. Carbon tetrachloride has no dipole moment because of correct on the basis of their dipole moments? (1) its planar structure (1) BF3 > NF3 > NH3 (2) NF3 > BF3 > NH3 (2) its regular tetrahedral structure (3) NH3 = NF3 > BF3 (4) NH3 > NF3 > BF3 (3) similar electron affinities of carbon and chlorine 164. Resonating structures have different (4) none of these (1) atomic arrangements (2) electronic arrangements 173. The molecule which has zero dipole moment is (3) function groups (1) SO2 (2) PCl3 (4) alkyl groups (3) XeF4 (4) CHCl3 174. Molecule AB has a bond length of 1.617 Å and a 165. Which among the following resonance structures of dipole moment of 0.38 D. The fractional charge on N3– satisfies the octet rule but is ruled out as a each atom (absolute magnitude) is (e0 = 4.802 × 10–10 resonance structure? esu) (I) (II) (1) 0 (2) 0.05 (3) 0.5 (4) 1.0 (III) (IV) (1) IV only (2) I and IV only 175. Bond-length of HCl is; 1.275 Å (e = 4.8 × 10–10 esu). (3) I only (4) II and III only If µ = 1.02 D then HCl is (1) 100% ionic (2) 83% covalent 166. Resonance is due to (3) 50% covalent (4) 40% ionic (1) Delocalization of sigma electrons (2) Delocalization of pi electrons 176. Calculate the % ionic character in LiF from following (3) Migration of H atoms data: (4) Migration of protons µLiF = 6.32 D dLiF = 0.156 nm 167. For which value of ‘x’, the dipole moment of the (1) 84.32% (2) 20.34% (3) 15.68% (4) 100% molecule PClxF5 – x is zero (1) 4 (2) 2 177. What is not true about resonance? (3) 3 (4) 1 (1) The resonating structures are hypothetical (2) The unpaired electrons in various resonating 168. Of the following molecules, the one, which has structures are same permanent dipole moment, is (3) Hybrid structure is most energetic (1) SiF4 (2) BF3 (4) Hybrid structure is least energetic (3) PF3 (4) PF5 178. Which of the following conditions is not correct for 169. Which of the following has the least dipole moment? resonating structures? (1) NF3 (2) SO3 (1) The contributing structures must have the same (3) XeO3 (4) NH3 number of unpaired electrons (2) The contributing structures should have almost 170. The dipole moment of the given molecules are such similar energies that (3) The contributing structures should be so (1) BF3 > NF3 > NH3 (2) NF3 > BF3 > NH3 written that unlike charges reside on atoms that (3) NH3 > NF3 > BF3 (4) NH3 > BF3 > NF3 are far apart (4) The positive charge should be present on the 171. RQ. (156) electropositive element and the negative charge on the electronegative element 14 179. Two hybrid orbitals have a bond angle of 120°. The 187. Species having zero dipole moment: percentage of s-character in the hybrid orbital is (1) XeF4 (2) SO2 nearly: (3) SF4 (4) CH2Cl2 (1) 25% (2) 33% (3) 50% (4) 66% 188. RQ. (157) 180. Resonance is not shown by 189. Among NO3 ,CO32 ,ClO3 ,SO32 and BO33 the non- (1) C6H6 (2) NO2 planar species are – (3) CO32 (4) H2O (1) CO32 ,SO32 ,BO33 (2) ClO3 , SO32 181. BeF2 has zero dipole moment whereas H2O has dipole moment because: (3) NO3 , CO32 , BO33 (1) Water is linear (4) NO3 , SO32 , BO33 (2) H2O is bent (3) F is more electronegative than O 190. RQ. (168) (4) Hydrogen bonding is present in H2O 191. The dipole moments of the given molecules are such 182. Which of the following molecule have zero dipole that – moment: (1) BF3 > NF3 > NH3 (1) BF3 (2) NF3 > BF3 > NH3 (2) CH2Cl2 (3) NH3 > NF3 > BF3 (3) NF3 (4) NH3 > BF3 > NF3 (4) SO2 192. The molecule BF3 and NF3 both are covalent 183. Which of the following species are polar: (1) C6H6 (2) XeF2 compounds. But BF3 is non-polar and NF3 is polar. (3) SO2 (4) SF4 The reason is that- (5) SF6 (1) boron is a metal and nitrogen is a gas in Correct answer is: uncombined state (1) (2) & (4) (2) (1), (2) & (5) (2) BF3 bonds have no dipole moment whereas (3) (1) & (5) (4) (3) & (4) NF3 bonds have dipole moment (3) atomic size of boron is smaller than that of 184. Dipole moment is shown by : nitrogen (1) 1, 4-Dichlorobenzene (4) BF3 is symmetrical molecule where as NF3 is (2) Cis 1, 2-dichloroethene unsymmetrical (3) Trans -1, 2-dichloro ethene (4) Benzene 193. Which of the following molecules shows maximum dipole moment – 185. RQ. (156) Br Br (1) (2) 186. What conclusion can be draw from the fact that BF3 Br has no dipole moment but PF3 does: Br (1) BF3 is not symmetrical but PF3 is symmetrical Br (2) BF3 molecule must be linear (3) Atomic radius of P is larger than that of B (3) (4) All have the same (4) BF3 molecule must be planar triangular Br 15 VSEPR Theory 194. Predict the correct order of repulsion among the 202. Among the following molecules: SO2, SF4, ClF3, BrF5 following: and XeF4 which of the following shapes does not (1) bond pair - bond pair > lone pair - bond pair > describe any of the molecules mentioned? lone pair - lone pair (1) Bent (2) lone pair - bond pair > bond pair-bond pair > (2) Trigonal bipyramidal lone pair - lone pair (3) See-saw (3) lone pair - lone pair > lone pair - bond pair > (4) T-shape bond pair-bond pair (4) lone pair - lone pair > bond pair-bond pair > 203. In which of the following molecule/ion, all the bonds lone pair - bond pair are not equal? (1) XeF4 (2) BF4 195. Which of the following molecules has more than one (3) C2 H4 (4) SiF4 lone pair? (1) SO2 (2) XeF2 (3) SiF4 (4) CH4 204. Incorrect matching amongst the following is: (i) Linear - H2O, SO2 196. In the structure of ClF3, the number of lone pairs of (ii) V-shaped - :CH2 , SnCl2 electrons on central atom ' Cl ' is: (iii) See Saw – SF4 , TeCl4 (1) one (2) two (iv) T-shaped - ICl3 , ClF3 (3) four (4) three (1) only (i) (2) both (ii and (ii) (3) only (iii) (4) both (iii) and (iv) 197. The central atom of which one of the following molecules, has 3 bond pairs and 2 lone pairs of electrons in its valence shell? 205. According to VSEPR theory molecule having T- (1) Boron trifluoride shape is: (2) Phosphorous trichloride (1) ClF3 (2) NH3 (3) Chlorine trifluoride (3) BF3 (4) H2 O (4) Xenon trioxide 206. Which of the following has a regular geometry? 198. Number of b.p. and l.p. in NO3 is: (1) CHCl3 (2) PCl3 (1) 3 b.p. + 1l.p. (2) 4 b.p. + 0 l.p. (3) 2 b.p. + 2 l.p. (4) 1 b.p. + 1 l.p. (3) XeF6 (4) SF4 199. SF4 can be classified as 207. Assertion: ClF3 has T-shape structure. (1) AB4 type (2) AB4E type Reason: It has two lone pairs arranged at 180º angle. (3) AB4E2 type (4) none of these (1) If both assertion and reason are true and reason 200. Pentagonal bipyramidal structure contains bond is the correct explanation of assertion. angles approximately (2) If both assertion and reason are true but reason (1) 120°, 90°, 180° (2) 120°, 72°, 180° is not the correct explanation of assertion. (3) 72°, 90°, 120° (4) 72°, 90°, 180° (3) If assertion is true but reason is false. (4) If both assertion and reason are false. 201. In which of the following molecules, the central atom has two lone pairs of electrons? 208. Which of the following molecules is linear in shape? (1 SF4 (2) BrF5 (1) XeF6 (2) XeO3 (3) SO2 (4) XeF4 (3) XeF4 (4) XeF2 16 209. The shape of XeF2 is: (1) Linear (2) Bent 216. The shape of XeO3 is: (3) T-shaped (4) None of these (1) T-shaped (2) Tetrahedral (3) Triangular planar (4) Pyramidal 210. Which of the following is planar? (1) XeO4 (2) XeO2 F2 217. The molecule which has T-shaped structure is: (3) XeO3 F2 (4) XeF4 (1) BCl3 (2) NCl3 (3) ICl3 (4) PCl3 211. The shape of ICl5 is: (1) triangular bipyramidal 218. The shape of the ICl3 molecule is: (2) octahedral (1) Tetrahedral (2) trigonal (3) square pyramidal (3) pyramidal (4) T-shaped (4) pentagonal planar 219. The geometry around the central atom in ClF4 is 212. In XeF2, XeF4 and XeF6 the number of lone pair of (1) square planar (2) square pyramidal electrons on Xe is respectively. (3) octahedral (4) trigonal bipyramidal (Atomic numbers: F = 9, Xe = 54) (1) 2, 3, 1 (2) 1, 2, 3 220. According to VSEPR model, the shape of [XeOF5 ] (3) 4, 1, 2 (4) 3, 2, 1 is (1) octahedral 213. The non-linear structure is assumed by (2) trigonal bipyramidal (1) SnCl2 (2) NCO (3) square pyramidal (3) NO +2 (4) CS2 (4) pentagonal monopyramidal 214. Molecular shapes of SF4 , CF4 and XeF4 are: 221. Among SF4 , BF4 , XeF4 and ICl4 the number of (1) same with 2,0 and 1 lone pairs of electrons species having two lone pair of electrons on the respectively. central atom according to VSEPR theory is (2) same with 1,1 and 1 lone pairs of electrons (1) 2 (2) 3 respectively. (3) 4 (4) 0 (3) different with 1,0 and 2 lone pairs of electrons respectively. 222. The total number of lone pairs of electrons in I3 is (4) different with 1,1 and 1 lone pairs of electrons (1) Zero (2) Three respectively. (3) Six (4) Nine 215. Match List I with List II & select the correct answer: List I List II 223. According to VSEPR theory, the geometry (with lone A. ICl 1. Linear pair) around the central iodine in I3+ and I3 ions 2 B. BrF2 2. Pyramidal respectively are (1) tetrahedral and tetrahedral C. ClF4 3. Tetrahedral (2) trigonal bipyramidal and trigonal bipyramidal D. AlCl4 4. Square planar (3) tetrahedral and trigonal bipyramidal 5. Angular (4) tetrahedral and octahedral (1) (A – 1), (B – 2), (C – 4), (D – 5) 224. The structure of XeF2 and XeO2F2 respectively are: (2) (A – 4), (B – 5), (C – 2), (D – 3) (1) bent, tetrahedral (3) (A – 1), (B – 5), (C – 4), (D – 3) (2) linear, square planar (4) (A – 5), (B – 1), (C – 3), (D – 4) (3) linear, see-saw 17 (4) bent, see-saw (C) [ClF2 ] , [ClO4 ] 225. The molecule with highest number of lone-pairs and has a linear shape based on VSEPR theory is: (D) XeO3 , SO3 (1) CO2 (2) I3 (1) (A) and (B) only (2) (A) and (C) only (3) NO 2 (4) NO 2 (3) (A), (B) and (C) only (4) (B), (C) and (D) only 226. The number of lone pair(s) of electrons on the central atom in [BrF4 ] , XeF6 and [SbCl6 ]3 are, 231. The number of lone-pairs are identical in the pairs respectively, (1) XeF4 ,ClF3 (2) XeO 4 , ICl 4 (1) 2,0 and 1 (3) XeO2 F2 , ICl4 (4) XeO4 , ClF3 (2) 1,0 and 0 (3) 2,1 and 1 (4) 2,1 and 0 232. The correct non-linear and iso-structural pair is (1) SCl2 , I3 (2) SCl2 , I3 227. The geometry of the molecule XeO2 F2 is (3) SCl2 , ClF2 (4) I3 , ClF2 (1) distorted octahedral (2) square planar 233. According to VSEPR theory, the molecule/ion having (3) trigonal bipyramidal ideal tetrahedral shape is (4) tetrahedral (1) SF4 (2) SO 24 228. Among the following, the isoelectronic and (3) S2Cl2 (4) SO2Cl2 isostructural pair is: (1) CO2 and SO2 234. According to VSEPR theory, the most probable shape of the molecule having 4 electron pairs in the outer (2) SO3 and SeO3 shell of the central atom is (3) NO 2 and TeO 2 (1) Linear (2) Tetrahedral (4) SiO 44 and PO34 (3) Hexahedral (4) Octahedral 229. Match list I (compounds) with list II (structures), and select the correct answer using the codes given below 235. In which of the following species maximum atom can List I List II lie in same plane? (a) XeO (i) square planar (1) XeF2O2 (2) PCl5 4 (b) BrF4 (ii) tetrahedral (3) AsH 4 (4) XeF4 (c) SeCl4 (iii) Distorted tetrahedral 236. Correct statement regarding molecules SF4, CF4 and (1) (a – ii) (b – iii) (c – i) XeF4 are: (2) (a – iii) (b – i) (c – ii) (1) 2, 0 and 1 lone pairs of central atom respectively (3) (a – ii) (b – i) (c – iii) (2) 1, 0 and 1 lone pairs of central atom respectively (4) (a – i) (b – ii) (c – iii) (3) 0, 0 and 2 lone pairs of central atom respectively (4) 1, 0 and 2 lone pairs of central atom respectively 230. Among the following pairs, those in which both species have similar structures are 237. The geometrical arrangement of orbitals and shape of (A) N3 , XeF2 I3 are respectively: (B) [ICl4 ] , [PtCl 4 ]2 (1) trigonal bipyramidal geometry, linear shape (2) hexagonal geometry, T-shape 18 (3) trigonal planar geometry, triangular shape (I) The order of repulsion between different pair (4) tetrahedral geometry, pyramidal shape of electrons is lp – lp > lp – bp > bp – bp 238. The structure of the noble gas compound XeF4 is: (II) In general, as the number of lone pair of (1) square planar
