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

The molar heats of fusion and vaporisation of benzene are $10.9$ and $31.0 \ kJ \ mol^{-1}$ respectively. The changes in entropy for the solid $\rightarrow$ liquid and liquid $\rightarrow$ vapour transitions for benzene are $x$ and $y \ JK^{-1} \ mol^{-1}$,respectively. The value of $(y-x)$ (in $JK^{-1} \ mol^{-1}$) is (At $1 \ atm$,benzene melts at $5.5^{\circ} C$ and boils at $80^{\circ} C$).

Which one of the following is always not negative?

If the standard enthalpy of sublimation $(\Delta_{sub} H^{\circ})$ of solid $CO_2$,naphthalene,$Li$ and $Na$ are $25.2, 73.0, 162, 108 \ kJ \ mol^{-1}$ respectively,the order of ease of sublimation of these substances is:

One mole of an ideal gas is allowed to expand freely and adiabatically into vacuum until its volume has doubled. Which of the following statements is $NOT$ true concerning this expansion?

In which of the following processes does entropy increase?