List-I contains some process/reactions, while List-II contains changes in different functions, match the appropriate. List - I List - II (A) Adiabatic reversible compression of an ideal gas (P) Δ U =

Question

List-I contains some process/reactions, while List-II contains changes in different functions, match the appropriate.

List - I	List - II
(A) Adiabatic reversible compression of an ideal gas	(P) $Δ U = 0$
(B) $C_{4} H_{8} (g) + 6 O_{2} (g) \frac{2 5 ^{\circ} C}{1 atm} 4 CO_{2} (g) + 4 H_{2} O (1)$	(Q) $Δ S_{sys} > 0$
(C) Isothermal compression of an ideal gas	(R) $Δ H < 0$
(D) $H_{2} O (1) 1 atm T = 11 0^{\circ} C H_{2} O (g)$	(S) $Δ T > 0$
	(T) $Δ G > 0$

TestHub · Accepted Answer

Explain Question: The question is asking about the correct match of the different processes/reactions with changes in different functions.

Concept:

For Adiabatic Reversible Compression of an Ideal Gas:

Internal Energy ( $Δ U$ ): Increases

* Since no heat is added ( $Q = 0$ ), and work is done on the gas:

$Δ U = Q + W$

For compression, $W$ is positive (work done on the system is positive), so $Δ U > 0$ .

* Relation (for ideal gas):

$Δ U = n C_{V} Δ T$

Enthalpy ( $Δ H$ ): Increases

* For ideal gases, enthalpy depends only on temperature:

$Δ H = n C_{P} Δ T$

Since temperature increases during adiabatic compression, $Δ H > 0$ .

Temperature ( $Δ T$ ): Increases

* During compression, molecules are forced closer together and gain kinetic energy, raising the temperature.

Gibbs Free Energy ( $Δ G$ ): Increases

* In a reversible adiabatic process, the entropy of the system stays constant ( $Δ S = 0$ ), but pressure increases, so:

$G = H - TS$

Solution:

A: Adiabatic reversible compression

$Δ U > 0$ , $Δ S_{sys} < 0$ , $Δ H > 0$ , $Δ T > 0$ , $Δ G = 0$

B: Combustion:

$Δ U \neq = 0$ , $Δ S < 0$ ( $Δ n_{g} < 0$ ), $Δ H < 0$

C: Isothermal:

$Δ U = 0$ , $Δ S_{sys} < 0$ , $Δ H = 0$ , $Δ G > 0$

D: H₂O(l) → H₂O(g):

Spontaneous at 1 atm and 110°C.

Final Answer: (C)

Chemistry - Thermodynamics - II Question with Solution | TestHub