Mole Concept Practice Questions | Target Pre-Medical 2026 PDF

  TARGET : PRE-MEDICAL 2026 NURTURE COURSE SOME BASIC CONCEPTS OF CHEMISTRY (MOLE CONCEPT) 1. 0 The volume of a gas at 0 C and 760 mm 8. 19.7 kg of...

  TARGET : PRE-MEDICAL 2026 NURTURE COURSE SOME BASIC CONCEPTS OF CHEMISTRY (MOLE CONCEPT) 1. 0 The volume of a gas at 0 C and 760 mm 8. 19.7 kg of gold was recovered from a pressure is 22.4 cc. The no. of molecules smuggler. How many atoms of gold were present in this volume is recovered ? (At. wt. of gold (Au) = 197) –3 (1) 10 NA (1) 100 –4 (2) 10 NA (2) 6.023 × 1023 –5 (3) 10 NA (3) 6.023 × 10 24 –2 (4) 10 NA (4) 6.023 × 10 25 2. 100 mL of PH3 when completely decomposed 9. Chlorine is prepared in the laboratory by treating produces phosphorus and hydrogen. The change manganese dioxide (MnO2) with aqueous in volume of the gas is - hydrochloric acid according to the reaction 2PH3(g) → 2P(s) + 3H2(g) 4HCl(aq) + MnO2(s) ® (1) 50 mL increase (2) 500 mL decrease → 2H2O() + MnCl2(aq) + Cl2(g) (3) 900 mL decrease (4) No change How many gram of HCl react with 5.0 g of 3. The volume of CO2 at STP obtained by heating manganese dioxide ? (At. wt. of Mn = 55) 1 g of CaCO3 will be (1) 2.12 g (2) 44.24 g (1) 1 L (2) 22.4 L (3) 8.4 g (4) 3.65 g (3) 0.224 L (4) 11.2 L 10. 510 milli g of a liquid on vapourisation produces 4. 3 L of mixture of propane (C3H8) & butane 510 cc at NTP. The molecular weight of liquid is - (C4H10) on complete combustion gives10 L CO2. (1) 0.224 (2) 2.24 (3) 224 (4) 22.4 Find the composition of original mixture. 11. An unknown amino acid has 0.032% sulphur by (1) C3H8, 2L and C4H10, 1L (2) C3H8, 3L and C4H10, 0L mass. If each molecule has one sulphur atom (3) C3H8, 1.5L and C4H10, 1.5L only, 1 g of amino acid has......... molecules :- 18 (4) C3H8, 0L and C4H10, 3L (1) 6.02 × 10 (2) 6.02 × 1019 5. The mass of a molecule of water : (3) 6.02 × 1024 (4) 6.02 × 1023 (1) 30 × 10–24 kg 12. 446 g of PbO, 46 g of NO2 and 16 g of O2 are (2) 3 × 10–26 kg allowed to react according to the equation :- (3) 1.5 × 10–26 kg 1 PbO + 2NO2 + O2 → Pb(NO3)2 (4) 2.5 × 10–27 kg 2 6. At NTP, 5.6 L of a gas weigh 8 g. The vapour The amount of Pb(NO3)2 that can be produced is density of gas is :- (At. wt. of Pb = 207) :- (1) 32 (2) 40 (1) 331 g (2) 662 g (3) 16 (4) 8 (3) 165.5 g (4) None of these 7. 0.01 mole of iodoform (CHI3) reacts with Ag to 13. A sample of organic compound on complete produce a gas whose volume at NTP is combustion gives 88 g CO2 and 36 g of H2O. The 2CHI3 + 6Ag → 6AgI(s) + C2H2(g) molecular formula of the compound may be :- (1) C4H6 (2) CH4 (1) 224 mL (2) 112 mL (3) 336 mL (4) None of these (3) C2H4 (4) C2H6 E Your Target is to secure Good Rank in Pre-Medical 2026   NURTURE COURSE TARGET : PRE-MEDICAL 2026 14. Volume at NTP of 0.22 g of CO2 is same as that of 22. The vapour densities of two gases are in the ratio (1) 0.01 g of hydrogen of 1 : 3. Their molecular masses are in the ratio (2) 0.085 g of NH3 of :- (3) 320 mg of gaseous SO2 (1) 1 : 3 (2) 1 : 2 (4) All of the above. (3) 2 : 3 (4) 3 : 1 15. 23. 22 The weight of 1 × 10 molecules of CuSO4. Calculate the number of atoms present in 7.1 g 5H2O is (At. wt. of Cu = 63.5) of chlorine? (1) 41.44 g (2) 414.5 g (1) 0.2 NA (2) 0.3 NA (3) 4.144 g (4) 4145 g (3) 0.4 NA (4) 0.5 NA 16. A hydrocarbon contain 80%C. The vapour 24. For reaction A + 2 B → C. The amount of density of compound is 30. Molecular formula of C formed by starting the reaction with 5 mole of compound is :- A and 8 mole of B is : ® (1) CH3 (2) C2H6 (1) 5 mol (2) 8 mol (3) C4H12 (4) All of these (3) 16 mol (4) 4 mol 17. Which of the following has maximum mass :- 25. In a compound, x is 75.8% and y is 24.2% by (1) 0.1 gram atom of carbon weight present. If atomic weight of x and y are (2) 0.1 mol of ammonia 24 and 16 respectively. Then calculate the 22 (3) 6.02 × 10 molecules of hydrogen empirical formula of the compound. (4) 1120 cc of carbon dioxide at STP (1) x2y (2) xy2 (3) xy (4) x3y3 18. What mass of NaCl would be decomposed by 26. At 25°C for complete combustion of 5 mol 98 g of H2SO4 if 120 g of NaHSO4 and propane (C3H8). The required volume of O2 at 27.5 g of HCl are produced in a reaction. STP will be. Assuming that law of mass conservation is true: (1) 560 L (2) 560 mL (1) 4.95 g (2) 49.5 g (3) 360 L (4) 360 mL (3) 0.495 g (4) 495 g 27. 1.5 moles of O2 combines with Mg to form oxide 19. Equal mass of oxygen, hydrogen and methane MgO. The mass of Mg (At. mass 24) that has are taken in a container in identical conditions. combined is 2Mg + O2 → 2MgO What is the ratio of their mole :- (1) 72 g (2) 36 g (1) 1 : 16 : 1 (2) 1 : 16 : 2 (3) 24 g (4) 94 g (3) 8 : 1 : 8 (4) 16 : 1 : 8 28. At STP, for complete combustion of 3 g C2H6 20. One litre of a certain gas weighs 1.16 g at STP. the required volume of O2 will be - The gas may be - (1) 78.4 L (2) 7.84 L (1) C2H2 (2) CO (3) 2.78 L (4) 6.23 L (3) O2 (4) NH3 29. 0.6 g of carbon was burnt in the air to form CO2. 21. When 40 cc of slightly moist hydrogen chloride The number of molecules of CO2 introduced into gas is mixed with 20 cc of ammonia gas the final the air will be : volume of gas left at the same temperature and C + O2 → CO2 pressure will be (1) 6.02 × 10 23 NH3(g) + HCl(g) →NH4Cl(s) (2) 3.01 × 10 23 (1) 20 cc (2) 40 cc (3) 6.02 × 10 22 (3) 60 cc (4) 100 cc (4) 3.01 × 10 22 Your Target is to secure Good Rank in Pre-Medical 2026 E   TARGET : PRE-MEDICAL 2026 NURTURE COURSE 30. 5 L of gas at STP weighs 6.25 g. What is the 35. The number of oxygen atoms in 4.4 g of CO2 is gram molecular weight ? approx. 23 (1) 1.25 (2) 14 (1) 1.2 × 10 (3) 28 (4) 56 (2) 6 × 1022 23 31. Two elements X (At wt = 75) and Y (At wt = 16) (3) 6 × 10 23 combine to give a compound having 75.8% of (4) 12 × 10 X. The empirical formula of compound is : 36. 1 mole of CH4 contains : (1) XY (1) 6.02 × 1023 atoms of H (2) X2Y (2) 4 g atom of hydrogen 23 (3) X2Y2 (3) 1.81 × 10 molecules of CH4 (4) X2Y3 (4) 3.0 g of carbon. 32. –1 The density of air is 0.001293 g mL at NTP. 37. Calculate the number of atoms present in one ® Its vapour density is :- drop of water having mass 1.8 g. (1) 143 (2) 14.53 (1) 0.3 NA (2) 0.2 NA (3) 1.43 (4) 0.143 (3) 0.1 NA (4) 0.01 NA 33. One mol of CO2 contains – 38. In the reaction, 4A + 2B + 3C → A4B2C3 (1) 3 atom what will be the number of moles of product 23 (2) 18.1 × 10 molecules of CO2 formed, starting from 1 mole of A, 0.6 mole of 23 (3) 6.02 × 10 atom of oxygen B and 0.72 mole of C :- 23 (4) 6.02 × 10 atom of carbon (1) 0.25 (2) 0.3 (3) 2.4 (4) 0.24 34. Which one of the following pairs of gases 39. In an organic compound of molar mass contains the same number of molecules ? –1 108 g mol C, H and N atoms are present in (1) 16 g of O2 and 14 g of N2 9 : 1 : 3.5 by weight. Molecular formula can be:- (2) 8 g of O2 and 22 g of CO2n (1) C6H8N2 (2) C7H10N (3) 28 g of N2 and 22 g of CO2 (3) C5H6N3 (4) C4H18N3 (4) 32 g of O2 and 32 g of N2 ANSWER KEY Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Ans 1 1 3 1 2 3 2 4 3 4 1 3 3 4 3 Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Ans 3 4 2 2 1 1 1 1 4 1 1 1 2 4 3 Que. 31 32 33 34 35 36 37 38 39 Ans 4 2 4 1 1 2 1 4 1 E Your Target is to secure Good Rank in Pre-Medical 2026