An ideal gas undergoes a reversible isothermal expansion from state $I$ to state $II$ followed by a reversible adiabatic expansion from state $II$ to state $III$. The correct plot$(s)$ representing the changes from state $I$ to state $III$ is(are)
($p$ : pressure,$V$ : volume,$T$ : temperature,$H$ : enthalpy,$S$ : entropy)

The enthalpies of combustion of cyclohexane $(C_6H_{12})$, cyclohexene $(C_6H_{10})$ and $H_2$ are $-3920 \text{ kJ mol}^{-1}$, $-3800 \text{ kJ mol}^{-1}$ and $-241 \text{ kJ mol}^{-1}$ respectively. The enthalpy of hydrogenation of cyclohexene is

For the following combustion reaction occurring in an automobile: $2C_{8}H_{18(g)} + 25O_{2(g)} \to 16CO_{2(g)} + 18H_{2}O_{(g)}$,what are the signs of $\Delta H$,$\Delta S$,and $\Delta G$?

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 $80^{\circ} C$).

In an adiabatic process,the work involved during expansion or compression of an ideal gas is given by

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: