NEET Spontaneity & Entropy Practice Questions With Solutions

NEET Chemistry Spontaneity & Entropy Practice Questions

Question 1.

In which of the following processes entropy increases?

AA liquid evaporates to vapour.

BTemperature of a crystalline solid lowered from \(130~\text{K}\) to \(0~\text{K}.\)

C\(2 \mathrm{NaHCO}_{3(\mathrm{~s})} \rightarrow \mathrm{Na}_2 \mathrm{CO}_{3(\mathrm{~s})}+\mathrm{CO}_{2(\mathrm{~g})}+\mathrm{H}_2 \mathrm{O}_{(\mathrm{g})}\)

D\(\mathrm{Cl}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{Cl}_{(\mathrm{g})}\)

Question 2.

For irreversible expansion of an ideal gas under isothermal condition, the correct option is :

A

∆ U = 0, ∆ S_{total} \neq 0

B

∆ U \neq 0, ∆ S_{total} = 0

C

∆ U = 0, ∆ S_{total} = 0

D

∆ U \neq 0, ∆ S_{total} \neq 0

Question 3.

If for a certain reaction

∆_{r} H

is 30 kJ mol^–1 at 450 K, the value of

∆_{r} S

(in JK^–1 mol^–1) for which the same reaction will be spontaneous at the same temperature is:

A70

B-33

C33

D-70

Question 4.

For a sample of a perfect gas when its pressure is changed isothermally from P_i to P_f, the entropy change is given by:

A

∆ s = nR

In

(\frac{p_{f}}{p_{i}})

B

∆ s = nR

In

(\frac{p_{i}}{p_{f}})

C

∆ s = nRT

In

(\frac{p_{f}}{p_{i}})

D

∆ s = RT

In

(\frac{p_{i}}{p_{f}})

Question 5.

A reaction occurs spontaneously if:

AT∆S > ∆H and ∆H is +ve and ∆S are –ve

BT∆S = ∆H and both ∆H and ∆S are +ve

CT∆S < ∆H and both ∆H and ∆S are +ve

DT∆S > ∆H and both ∆H and ∆S are +ve

Question 6.

Which of the following pairs of chemical reactions is certain to result in a spontaneous reaction:

AEndothermic and decreasing disorder

BExothermic and increasing disorder

CEndothermic and increasing disorder

DExothermic and decreasing disorder

Question 7.

Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is:

A

{ΔS}_{system} - {ΔS}_{surrounding} > 0

B

{ΔS}_{system} > 0 only

C

{ΔS}_{surroundings} > 0

only

D

{ΔS}_{system} + {ΔS}_{surrounding} > 0

Question 8.

What is the entropy change (in JK^–1 mol^–1) when one mole of ice is converted into water at 0 ºC? (The enthalpy change for the conversion of ice to liquid water is 6.0 KJ mol^–1 at 0 ºC)

A20.13

B2.013

C2.198

D21.98

Question 9.

The unit of entropy is:

AJK^–1 mol^–1

BJ mol^–1

CJ^–1K^–1 mol^–1

DJK mol^–1

Question 10.

At 27ºC latent heat of fusion of a compound is 2930 J/mol. Entropy change is:

A9.77 J/mol K

B10.77 J/mol K

C9.07 J/mol K

D0.977 J/mol K