Question

Which is/are true about isothermal process of an ideal gas.

• A. $w=0$
• B. $\Delta U=0$
• C. $\Delta H=0$
• D. $\Delta \left(nRT\right)=0$

Answer 1

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

The correct options are
B $\Delta U=0$
C $\Delta H=0$
D $\Delta \left(nRT\right)=0$

We know for isothermal process, temperature remains constant.
So, $\Delta T=0$ hence,
$\Delta \left(nRT\right)=0$

As the temperature remains constant so internal energy also remains constant for an ideal gas,
$\Delta U=0$

and we know,
$\Delta H=\Delta U+\Delta \left(nRT\right)$
As $\Delta Uand\Delta \left(nRT\right)$ are $0$ so,
$\Delta H=0$
or
we can also say as $\Delta H=n{C}_p\Delta T$
$\Delta T=0$ so, $\Delta H=0$