Maharashtra Board Class 12 Chemistry Question Paper 2024 PDF

## Chemistry (55) **General Instructions:** The question paper is divided into four sections. **(1) Section A:** * **Q. No. 1:** Contains Ten multiple choice type of questions carrying One mark each. Only the first attempt will be considered for evaluation. * **Q. No. 2:** Contains Eight very...

## Chemistry (55) **General Instructions:** The question paper is divided into four sections. **(1) Section A:** * **Q. No. 1:** Contains Ten multiple choice type of questions carrying One mark each. Only the first attempt will be considered for evaluation. * **Q. No. 2:** Contains Eight very short answer type of questions carrying One mark each. **(2) Section B:** Q. No. 3 to Q. No. 14 are Twelve short answer type of questions carrying Two marks each. (Attempt any Eight) **(3) Section C:** Q. No. 15 to Q. No. 26 are Twelve short answer type of questions carrying Three marks each. (Attempt any Eight) **(4) Section D:** Q. No. 27 to Q. No. 31 are Five long answer type of questions carrying Four marks each. (Attempt any Three) **(5)** Use of log table is allowed. Use of calculator is not allowed. **(6)** Figures to the right indicate full marks. **(7)** Given: * $R = 8.314 \, J.K^{-1}.mol^{-1}$ * $N_A = 6.022 \times 10^{23}$ * $F = 96500C$ --- ## Section - A **Q. 1**. Select and write the correct answer for the following multiple choice type of questions: **(i)** The spin only magnetic moment of $Cr^{3+}$ cation is: * (a) 3.742 BM * (b) 3.755 BM * (c) 3.873 BM * (d) 3.633 BM **(ii)** The linkage present in Lactose is: * (a) $\alpha, \beta - 1,2$ – glycosidic linkage * (b) $\alpha - 1,4$ - glycosidic linkage * (c) $\beta - 1,4$ - glycosidic linkage * (d) $\alpha - 1,4$ - glycosidic linkage **(iii)** The product of the following reaction is: $C_2H_5-C-CH_3 \xrightarrow[H_2/\Delta]{Ni}?$ * (a) $CH_3-CH_2-CH_2-CH_2-OH$ * (b) $CH_3-CH-CH_2-CH_3$ $OH$ * (c) $CH_3-CH_2-CH_2-CH_3$ * (d) $CH_3-CH_2-CH_2-COOH$ **(iv)** The pH of 0.001M HCl solution is: * (a) 10 * (b) 3 * (c) 2 * (d) 11 **(v)** The correct structure of complex having IUPAC name sodium hexanitrocobaltate (III) is * (a) $Na_3[Co(NO_2)_5]$ * (b) $Na_4[Co(NO_2)_6]$ * (c) $Na_3[Co(NO_2)_6]$ * (d) $Na_4[Co(NO_2)_5]$ **(vi)** The number of particles present in Face Centered Cubic Unit Cell is/are: * (a) 1 * (b) 2 * (c) 3 * (d) 4 **(vii)** The monomer used in preparation of teflon is: * (a) E caprolactum * (b) vinyl chloride * (c) styrene * (d) tetrafluoroethene **(viii)** Among the following vinylic halide is: * (a) $R-CH-R$ $X$ * (b) $CH_2 = CH - X$ * (c) A hexagon with a single bond connected to X * (d) $CH_2 = CH - CH_2 - X$ **(ix)** The product of hydrolysis of propyne in the presence of 1% $H_2SO_4$ and 40% $H_2SO_4$ is: * (a) methanal * (b) ethanal * (c) propanal * (d) propanone **(x)** If unit of rate constant is mol $dm^{-3}s^{-1}$, the order of reaction would be: * (a) zero * (b) 1 * (c) 2 * (d) 3 **Q. 2**. Answer the following questions: **(i)** Write the name of metal nanoparticle used to remove E.coli bacteria from water. **(ii)** Write the name of reduction product formed when ethyl cyanide is treated with sodium and alcohol. **(iii)** Complete the reaction: $CH_3CH_2Cl \xrightarrow[alc.\Delta]{AgCN}?$ **(iv)** Calculate effective atomic number of $[Co(NH_3)_6]^{3+}$ ion. --- ## Section - B Attempt any EIGHT of the following questions: **Q. 3**. Derive an expression for maximum work obtainable during isothermal reversible expansion of an ideal gas from initial volume ($V_1$) to final volume ($V_2$). **Q. 4**. What are interhalogen compounds? Write the chemical reaction, when chlorine reacts with dry slaked lime. **Q. 5**. What is nano material? Write the reaction involved in sol-gel process during hydrolysis. **Q. 6**. Write classification of proteins with an example. **Q. 7**. Calculate the time required to deposit 2.4 g of Cu, when 2.03 A of current passed through $CuSO_4$ solution. (At. mass of Cu = 63.5 g.mol-1) **Q. 8**. Why amines are basic in nature? Among dimethylamine ($pK_b = 3.27$) and diethylamine ($pK_b = 3.0$), which one is more basic? **Q. 9**. Explain buffer action of sodium acetate-acetic acid buffer. **Q. 10**. Write preparation of (a) diethyl ether (b) ethyl cyanide from ethyl bromide. **Q. 11**. Henry's constant for $CH_3Br(g)$ is 0.159 mol $dm^{-3}.bar^{-1}$ at $25^\circ C$. Calculate its solubility in water at $25^\circ C$, if its partial pressure is 0.164 bar. **(Q.) 12**. Write the structure and name of monomer of: **(a)** Nylon-6 **(b)** Natural rubber **Q. 13**. Define Lanthanide contraction. Write the balanced chemical equations when acidified $K_2Cr_2O_7$ reacts with $H_2S$. **Q. 14**. Derive the relationship between molar mass, density of the substance and unit cell edge length. --- ## Section - C Attempt any EIGHT of the following questions: **Q. 15**. What is osmotic pressure? How will you determine molar mass of solute from osmotic pressure? **Q. 16**. Write chemical reactions involved in: **(a)** Rosenmund reduction. **(b)** Gatterman Koch formylation. **(c)** Cannizzaro reaction of methanal. **Q. 17**. Calculate the standard enthalpy of combustion of methane, if the standard enthalpy of formation of methane, carbon dioxide and water are -74.8, -393.5 and -285.8 kJmol-1 respectively. **Q. 18**. What is the action of following on ethyl bromide? **(a)** silver nitrite **(b)** Mg in dry ether **(c)** alcoholic sodium hydroxide **Q. 19**. For the reaction $A + B \rightarrow P$. If [B] is doubled at constant [A], the rate of reaction doubled. If [A] is triple and [B] is doubled, the rate of reaction increases by a factor of 6. Calculate the rate law equation. **Q. 20**. Arrange the following in the increasing order of the property mentioned: (i) HOCl, $HClO_2$, $HClO_3$, $HClO_4$ (acidic strength) (ii) MF, MCl, MBr, MI (ionic character) (iii) HF, HCl, HBr, HI (thermal stability) **Q. 21**. Explain Wolf-Kishner reduction reaction. Write preparation of propanone by using ethanoyl chloride and dimethyl cadmium. **Q. 22**. Write postulates of Werner theory of co-ordination complexes. Write the name of a hexadentate ligand. **Q. 23**. Define electrochemical series and write its two applications. **Q. 24**. Identify 'A', 'B' and 'C' in following chain reaction and rewrite the chemical reactions: $CH_3CH_2OH \xrightarrow[Br_2]{red'P'} A \xrightarrow{KCN} B \xrightarrow{LiAlH_4} C$ **Q. 25**. Define acids and bases according to Bronsted-Lowry theory. Derive relationship between pH and pOH. **Q. 26**. Write the preparation of potassium dichromate from chromite ore. --- ## Section - D Attempt any THREE of the following questions : **Q. 27**. Convert the following: **(i)** acetaldehyde to isopropyl alcohol. **(ii)** cumene to phenol. **(iii)** anisole to phenol. Write two uses of neon. **Q. 28**. Define: **(i)** Extensive and Intensive properties **(ii)** Isobaric and Adiabatic processes * What are enzymes? * Write the atomic numbers of transuranium elements. **Q. 29**. Predict the type of cubic lattice of a solid element having edge length of 400 pm and density is 6.25 g/ml (Atomic mass of element = 60) * Define: Nanoscience * Write chemical reaction for the preparation of polyacrylonitrile. **Q. 30**. Derive the relation between half life period and rate constant for first order reaction. * Write the net cell reaction during discharging of lead accumulator. * Draw the structure of peroxymonosulphuric acid. **Q. 31**. Mention the number of unpaired electrons and geometry of following complexes: **(i)** $[NiCl_4]^{2-}$ **(ii)** $[Ni(CN)_4]^{2-}$ Convert the following: **(a)** Ethanenitrile into ethanal. **(b)** Cyclohexane into adipic acid.