Course Code: BCHCT-133
Assignment Code: BCHCT-133/TMA/2023
Maximum Marks: 100

Note: Attempt all questions. The marks for each question are indicated against it.

PART A: CHEMICAL ENERGETICS AND EQUILIBRIA

1. (a) State Zeroth law of thermodynamics and give the requirement for thermal equilibrium.

(b) Differentiate between a closed and an isolated thermodynamic system with the help of suitable examples.

(c) 0.25 mol of an ideal monoatomic gas undergoes isothermal expansion from a volume of \(2.0 \mathrm{dm}^{3}\) to \(10 \mathrm{dm}^{3}\) at \(27^{\circ} \mathrm{C}\). Calculate the maximum work that can be obtained from this process.

2. (a) Calculate the amount of heat required to increase the temperature of 2.00 moles of Argon gas from a temperature of \(200 \mathrm{~K}\) to \(500 \mathrm{~K}\) under isobaric conditions.

[Given: \(C_{p, \mathrm{~m}}=20.79 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\) ]

(b) Calculate \(\Delta H^{\circ}\) for the reaction

\(\mathrm{CO}_{2}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})\)

Given: \(\Delta \mathrm{H}\) for \(\mathrm{CO}_{2}(\mathrm{~g}), \mathrm{CO}(\mathrm{g})\) and \(\mathrm{H}_{2} \mathrm{O}(\mathrm{g})\) are \(-393.5,-111.31\) and \(-241.80 \mathrm{~kJ} \mathrm{~mol}^{-1}\) respectively.

(c) Differentiate between enthalpy driven and entropy driven reactions with the help of suitable examples.

3. (a) Define enthalpy of atomisation. The enthalpy of atomisation of graphite is found to be \(715 \mathrm{~kJ} \mathrm{mo1} 1^{-1}\), write the thermochemical equation for the process.

(b) Derive an expression for isothermal mixing of ideal gases.

(c) Fossil fuels are being replaced with hydrogen, much of it is being derived from methane, \(\mathrm{CH}_{4}\), in natural gas which uses the forward reaction of the equilibrium:

\(\mathrm{CH}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(g) \rightleftharpoons \mathrm{CO}(g)+3 \mathrm{H}_{2}(g)\)

What will be the expression for \(K_{c}\) for the above reaction?

4. (a) The successive ionisation constants of polyprotic acids are smaller and smaller. Explain. (b) Determine the acid-base nature of the aqueous solution obtained by dissolving \(\mathrm{NaNO}_{2}\)

in water to get \(0.01 \mathrm{M}\) solution at \(298 \mathrm{~K}\). [Given: \(K_{\mathrm{a}}\left(\mathrm{HNO}_{2}\right)=4.5 \times 10^{-4}\) ]

(c) Consider the equilibrium \(\mathrm{PCl}_{3}(g)+\mathrm{Cl}_{2}(g) \rightleftharpoons \mathrm{PCl}_{5}(g)\), This reaction is endothermic. What will be the change in the concentration of \(\mathrm{Cl}_{2}\) a) more \(\mathrm{PCl} 3\) is added b) more \(\mathrm{PCl} 5\) is added c) temperature is increased and d) the volume of the container is reduced.

5. (a) The sulphides of group IV cations are not precipitated in Group II. Explain.

(b) Arrange propanoic acid, ethanoic acid and 2-chloroethanoic acid in the increasing order of their acidities giving reasons.

(c) The solubility product of \(\mathrm{AgCl}\) is \(1.8 \times 10^{-10}\). Calculate the concentration of chloride ions required to precipitate silver ions from its \(0.01 \mathrm{M}\) solution.

PART B: FUNCTIONAL GROUP ORGANIC CHEMISTRY-I

6. (a) Complete the following reactions:

(i)

(ii)

(iii)

(iv)

\((\mathrm{v})\)

(b) Write the product for the following reaction. Explain product (s) formation using its mechanism.

7. (a) Why alkenyl and aryl halides are less reactive towards nucleophilic substitution?

(b) What is the best way to convert alcohol to alkyl halides? Explain with suitable examples. 8. (a) How you will carry out following conversions? Write all the steps involved in these conversions.

(i)

(ii)

(b) Identify suitable alkyl halides for the preparation of anisole and MTBE. Justify your answer.

Distinguish between crown ethers and cryptands.

(b) Find out suitable reagents for the following conversions:

(i)

(ii)

(iii) \(\mathrm{RCOCl} \longrightarrow \mathrm{RCHO}\)

(iv)

\((v)\)

10. Write the mechanism of the following reactions:
(a) Acid-catalyzed enolisation
(b) Claisen-Schmidt reaction