Question

The correct statements among the following is/ are

• A. $q_v=C_v\Delta T$ at constant volume
• B. Work done in free expansion of a real gas is not zero
• C. Work done in a reaction $Zn$ with $HCl$ in a closed container is zero
• D. Work done in adiabatic expansion is less than reversible isothermal expansion

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A $q_v=C_v\Delta T$ at constant volume
B Work done in free expansion of a real gas is not zero
C Work done in a reaction $Zn$ with $HCl$ in a closed container is zero
D Work done in adiabatic expansion is less than reversible isothermal expansion

A) $\Delta U=q+w$
At constant volume,
$\Delta U=q$
we know $\Delta U=C_v\Delta T$. Hence, A is true.

B) In the free expansion of a real gas, the gas must overcome intermolecular forces. Hence, some work is done

C) In a closed container $\Delta V=0$. Hence, work done is zero.

D) Since, there is a loss of temperature in adiabatic expansion, the work done will be less than the adiabatic expansion.