JEE Main 2026 — Chemistry Physical Chemistry

2026mcqmedium

Given below are two statements:

Statement I: For an ideal gas, heat capacity at constant volume is always greater than the heat capacity at constant pressure.

Statement II: In a constant volume process, no work is produced and all the heat withdrawn goes into the chaotic motion and is reflected by a temperature increase of the ideal gas.

In the light of the above statements, choose the correct answer from the options given below

Official previous-year question

Held on 4 Apr 2026 · Verified 6 Jul 2026.

Options

A
Both Statement I and Statement II are true
B
Both Statement I and Statement II are false
C
Statement I is true but Statement II is false
D
Statement I is false but Statement II is true

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Solution

For an ideal gas, the relationship between heat capacity at constant pressure ( $C_p$ ) and heat capacity at constant volume ( $C_v$ ) is given by Mayer's relation:

$C_p - C_v = R$

Since the universal gas constant $R$ is a positive value, $C_p > C_v$ . Thus, Statement I is false.

In a constant volume (isochoric) process, the change in volume $\Delta V = 0$ .

Work done, $W = P\Delta V = 0$ .

According to the first law of thermodynamics:

$\Delta U = q + W$

Since $W = 0$ , we get $\Delta U = q_v$ .

This means that in a constant volume process, no work is produced and all the heat absorbed by the system (withdrawn from the surroundings) goes entirely into increasing the internal energy (chaotic motion of the molecules). This increase in internal energy is reflected by an increase in the temperature of the ideal gas. Thus, Statement II is true.

Therefore, Statement I is false but Statement II is true.

Answer: Statement I is false but Statement II is true

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Solution

For an ideal gas, the relationship between heat capacity at constant pressure ( $C_p$ ) and heat capacity at constant volume ( $C_v$ ) is given by Mayer's relation:

$C_p - C_v = R$

Since the universal gas constant $R$ is a positive value, $C_p > C_v$ . Thus, Statement I is false.

In a constant volume (isochoric) process, the change in volume $\Delta V = 0$ .

Work done, $W = P\Delta V = 0$ .

According to the first law of thermodynamics:

$\Delta U = q + W$

Since $W = 0$ , we get $\Delta U = q_v$ .

Therefore, Statement I is false but Statement II is true.

Answer: Statement I is false but Statement II is true

JEE Main 2026 — Chemistry Physical Chemistry

Options

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

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JEE Main 2026 — Chemistry Physical Chemistry

Options

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry