$4 \ g$ of $NH_4NO_3$ were dissolved in $196 \ g$ of water at constant pressure in a calorimeter with a heat capacity of $160 \ J \ K^{-1}$. The temperature fell by $1.3 \ K$. The specific heat of the solution is $4.2 \ J \ K^{-1} \ g^{-1}$. The enthalpy of solution of $NH_4NO_3$ is $......$ $kJ \ mol^{-1}$.

The $C_p$ of an ideal gas is $10.314 \ J \ mol^{-1} \ K^{-1}$. One mole of this gas is expanded against a constant pressure of $p \ atm$. The change in temperature during expansion is $1.0 \ K$. The values of $q$ (in $J$) and $\Delta H$ (in $J \ mol^{-1}$) are respectively

Expansion of $1$ $mol$ of an ideal gas takes place from $2$ $L$ to $8$ $L$ at $300$ $K$ against a constant external pressure of $1$ $atm$. Calculate $\Delta S_{total}$ in $J$ $K^{-1}$ $mol^{-1}$.
(Given: $R = 8.3$ $J$ $K^{-1}$ $mol^{-1}$,$1$ $L$ $atm = 100$ $J$,$\ln 2 = 0.693$) (in $.5$)

One mole of an ideal gas at $900 \ K$ undergoes two reversible processes,$I$ followed by $II$,as shown in the graph. If the work done by the gas in the two processes is the same,the value of $\ln \frac{V_3}{V_2}$ is. . . . . . . . ($U$: internal energy,$S$: entropy,$p$: pressure,$V$: volume,$R$: gas constant). (Given: molar heat capacity at constant volume,$C_{V, m}$ of the gas is $\frac{5}{2} R$)

An ideal gas undergoes a cyclic process as shown in the figure.
$\Delta U_{BC} = -5 \ kJ \ mol^{-1}$,$q_{AB} = 2 \ kJ \ mol^{-1}$
$\Delta W_{AB} = -5 \ kJ \ mol^{-1}$,$W_{CA} = 3 \ kJ \ mol^{-1}$
Heat absorbed by the system during process $CA$ is......$kJ \ mol^{-1}$

The incorrect expression among the following is: