Which among the following are true for an irreversible isothermal expansion of an ideal gas?
$(i)$ $W = -Q$
$(ii)$ $\Delta U = 0$
$(iii)$ $\Delta H \neq 0$
$(iv)$ $\Delta T = 0$

The enthalpies of combustion of carbon and carbon monoxide are $-393.5 \, kJ \, mol^{-1}$ and $-283 \, kJ \, mol^{-1}$ respectively. The enthalpy of formation of carbon monoxide per mole is $....... \, kJ \, mol^{-1}$. (in $.5$)

Identify the correct statement$(s)$:

For a dimerization reaction,$2 A_{(g)} \rightarrow A_{2(g)}$ at $298 \ K$,$\Delta U^{\ominus} = -20 \ kJ \ mol^{-1}$,$\Delta S^{\ominus} = -30 \ J \ K^{-1} \ mol^{-1}$,then the $\Delta G^{\ominus}$ will be........ $J$

An ideal gas in a thermally insulated vessel at internal pressure $= P_1$,volume $= V_1$ and absolute temperature $= T_1$ expands irreversibly against zero external pressure,as shown in the diagram. The final internal pressure,volume and absolute temperature of the gas are $P_2, V_2$ and $T_2$,respectively. For this expansion,
$(A) \ q = 0$
$(B) \ T_2 = T_1$
$(C) \ P_2 V_2 = P_1 V_1$
$(D) \ P_2 V_2^\gamma = P_1 V_1^\gamma$

Standard enthalpy of vapourisation for $CCl_4$ is $30.5 \ kJ \ mol^{-1}$. Heat required for vapourisation of $284 \ g$ of $CCl_4$ at constant temperature is . . . . . . $kJ$. (Given molar mass in $g \ mol^{-1} ; C=12, Cl=35.5$ )