Entropy decreases during:

1. Crystallization of sucrose from solution

2. Rusting of iron

3. Melting of ice

4. Vaporization of camphor

At a temperature of 300K, what is the entropy change for the reaction given below?

2H₂ (g) + O₂ (g) $\to$2H₂O(l)

Standard entropies of H₂ (g), O₂(g) and H₂O(l) are 126.6, 201.20 and 68.0 JK^-1mol^-1 respectively.

1. -318.4 JK^-1mol^-1                           

2. 318.4 JK^-1mol^-1 

3. 31.84 JK^-1mol^-1                             

4. None of the above

Change in entropy is negative for:

1. Bromine (l)$\to$Bromine(g)

2. C(s) + H₂O(g) $\to$CO(g) + H₂(g)

3. N₂(g,10 atm)$\to$N₂(g,1 atm) 

4. Fe ( 1mol, 400 K) $\to$ Fe( 1mol, 300 K)

Which statements are correct?

(a) $2.303 \log \frac{{\mathrm{P}}_2}{{\mathrm{P}}_1}=\frac{∆{\mathrm{H}}_{\mathrm{vap}.}}{\mathrm{R}}\frac{\left[{\mathrm{T}}_2-{\mathrm{T}}_1\right]}{{\mathrm{T}}_1{\mathrm{T}}_2}$ is called Clausius-Clapeyron equation

(b) $\frac{∆{\mathrm{H}}_{\mathrm{vap}.}}{\mathrm{Boiling} \mathrm{Point}}=88 J mo{l}^{-1}{K}^{-1}$ is called Trouton's rule

(c) Entropy is a measure of unavailable energy, i.e.,

     unavailable energy = entropy x temperature

(d) All of the above

A gaseous system changes from state A(P₁, V₁, T₁) to B(P₂,V₂,T₂), B to C(P₃, V₃, T₃) and finally from C to A. The whole process may be called:

(a) reversible process                           

(b) cyclic process

(c) isobaric process                               

(d) spontaneous process

All the naturally occurring processes, i.e., spontaneous proceed spontaneously in a direction which leads to:

(1) decrease of free energy                     

(2) increase of free energy

(3) decrease of entropy                           

(4) increase of enthalpy

Warming ammonium chloride with sodium hydroxide in a test tube is an example of:

1. closed system                      2. Isolated system

3. open system                        4. None of these

Predict which of the following reaction(s) has a positive entropy change?

(i) Ag⁺ (aq) + Cl^-(aq) $\to$AgCl(s)

(ii) NH₄Cl(g) $\to$NH₃(g) + HCl(g)

(iii) 2NH₃(g)$\to$N₂(g) + 3H₂(g)

(1) i & ii

(2) iii

(3) ii & iii

(4) ii

For the following given equations and $∆\mathrm{H}°$ values, determine the enthalpy of reaction at 298 K for the reaction:

C₂H₄(g) + 6F₂(g) $\to$ 2CF₄(g) + 4HF(g)

H₂(g) + F₂(g) $\to$ 2HF(g)       $∆{\mathrm{H}}_1^{°}$= -537 kJ

C(s) + 2F₂(g) $\to$CF₄(g)         $∆{\mathrm{H}}_2^{°}$=-680 kJ

2C(s) + 2H₂(g) $\to$C₂H₄(g)    $∆{\mathrm{H}}_3^{°}$= 52 kJ

1. –1165 kJ

2. –2486 kJ

3. +1165 kJ

4. +2486 kJ

If $∆{\mathrm{H}}_{\mathrm{f}}^{°}$(C₂H₄) and $∆{\mathrm{H}}_{\mathrm{f}}^{°}$(C₂H₆) are x₁ and x₂ kcal/mol then heat of hydrogenation of C₂H₄ is :-

(1) x₁ + x₂

(2) x₁ - x₂

(3) x₂ - x₁

(4) x₁ + 2x₂