Find the enthalpy of neutralisation of $NH_4OH$ and $HCN$ in aqueous solution if the enthalpy of ionisation of $NH_4OH$ and $HCN$ are $7 \ kJ/mol$ and $8 \ kJ/mol$ respectively. Also,the enthalpy of neutralisation of $H^{+}$ and $OH^{-}$ is $-57.3 \ kJ/mol$.

Fill in the blanks given below:
$(i)$ The law of thermodynamics is actually the law of ......... .
$(ii)$ $A$ thermometer measures temperature according to the ......... law of thermodynamics.
$(iii)$ The foundation of thermochemistry is based on the ......... law of thermodynamics.
$(iv)$ The amount of heat required to raise the temperature of a substance by $1^{\circ}C$ is called the ......... of that substance.

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,
$(A) \ q = 0$
$(B) \ T_2 = T_1$
$(C) \ P_2 V_2 = P_1 V_1$
$(D) \ P_2 V_2^\gamma = P_1 V_1^\gamma$

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:

An ideal gas undergoes a reversible cyclic process as shown in the figure. The work done in this process is: (in $,V_1P_1$)

The heat of combustion of $CO$ at $290 \ K$ and constant volume is $-280.5 \ kJ$. What will be the heat of combustion at constant pressure in $kJ$?