BCHCT-133 EM 2025 SOLVED ASSIGNMENT

Description

ASSIGNMENT
CHEMICAL ENERGETICS, EQUILIBRIA AND FUNCTIONAL ORGANIC
CHEMISTRY I
Core Course in Chemistry
Course Code: BCHCT-133
Assignment Code: BCHCT-133/TMA/2025
Maximum Marks: 100
Note: Attempt all questions. The marks for each question are indicated against it.

PART A: CHEMICAL ENERGETICS AND EQUILIBRIA
1. (a) (i) Define chemical thermodynamics and outline its significance. (2)
(ii) Explain the concept of thermodynamic reversibility with the help of a suitable
example.
(3)
(b) (i) 223 J of heat was supplied to a thermodynamic system and its internal energy
was found to decrease by 92 J. Calculate the amount of associated work and state
whether the work was done by the system or done on the system?
(2)
(ii) Derive the relationship between the temperature and pressure for a reversible
adiabatic process.
(3)
2. (a) (i) 0.5 mole of an ideal gas is taken in a container at 298 K. Calculate the values of
its heat capacities at constant pressure and at constant volume conditions.
(2)
(ii) 1 mole of an ideal gas is allowed to undergo isothermal reversible expansion at
25°C from a volume of 10 dm3to 20 dm3. Calculate the maximum amount of
work done by the gas on the surroundings.
(3)
(b) (i) Derive the relationship between rU and rH. (2)
(ii) Describe the method for experimental determination of energy changes
accompanying chemical reactions under constant volume conditions.
(3)
3. (a) (i) State Hess’ law of constant heat summation and give its significance (2)
(ii) Using the bond enthalpy datafrom Table 3.2 of (Unit 3; p, 76), calculate the
enthalpy of hydrogenation of 1–propene.
(3)
(b) (i) Give the mathematical expressions for the thermodynamic and statistical
definitions of entropy.
(2)
(ii) Explain the effect of temperature on the enthalpy of a reaction and derive the
Kirchhoff’s equation.
(3)
4. (a) (i) What is residual entropy? What kind of systems show residual entropy? (2)
(ii) Explain the difference between enthalpy driven and entropy driven reactions. (3)
(b) (i) Define equilibrium constant and write the expressions for concentration
equilibrium constant for the following reaction
N2(g)+3H2(g) 2NH3(g)
(2)
4

(ii) For the following equilibrium reaction
2SO2(g)+O2(g) 2SO3(g) Kc=245(at 100 K)
the equilibrium concentrations are [SO2]=0.204,[O2]=0.0264 and [SO3]=0.368.
Show that the equilibrium will shift towards the reactants side if the
concentration of SO2 is suddenly doubled.
(3)
5. (a) (i) Define degree of hydrolysis and derive its relationship with hydrolysis constant (2)
(ii) Explain the effect of addition of inert gas to a gaseous equilibrium reaction under
the conditions of i) constant volume and ii) constant pressure.
(3)
(b) (i) Calculate the pH of 0.1 M aqueous solution of sodium formate at 298 K. [Given:
Ka (HCOOH) =1.7 X 10−4 at 298K
(2)
(ii) Define solubility product constant and derive an expression for the solubility
product constant for a sparingly soluble salt of M2A3 type having a solubility of S
mol dm–3.
(3)

PART B: FUNCTIONAL GROUP ORGANIC CHEMISTRY-I
6. (a) Both 1, 3, 5-cycloheptatrienyl cation and 1,3,5-cycloheptatriene have 6 π
elections , comments on the aromaticity of these compounds.
(5)
(b) Discuss the role of Lewis acids in halogenations and alkylation reactions of
benzene. Write the limitations of Freidel Crafts alkylation reaction.
(5)
7. (a) Nitro group is meta directing, explain. (5)
(b) What would be the final products of the reaction of HI with diethyl ether and
anisol? Write the mechanism of both the reactions.
(5)
8. (a) What is aldol condensation? Write its mechanism. (5)
(b) Arrange the following in order of their increasing reactivity towards SN2
substitution reactions: bromomethane, 1-bromo-propane, 2-bromopropane, 2
bormo-2-methyl propane. Justify your answer.
(5)
9. (a)
(b)
(c)
(d)
(e)
Write their representative reaction for the following reactions.
Sandmeyer reaction
Reimer-Tiemann reaction
Mannich reaction
Willgerodt reaction
Knoevenagel reaction
(5)
10 (a) Write the mechanism of Pinacol-pinacolone reaction. (5)
(b) How you will introduce a formyl group into phenol ring.