The incorrect expression among the following is:

Reversible expansion of an ideal gas under isothermal and adiabatic conditions are as shown in the figure.
$AB \to$ Isothermal expansion
$AC \to$ Adiabatic expansion
Which of the following options is not correct?

When $1 \ g$ equivalent of a strong acid reacts with a strong base,the heat released is $13.5 \ kcal$. When $1 \ g$ equivalent of $H_2A$ is completely neutralized against a strong base,$13 \ kcal$ is released. When $1 \ g$ equivalent of $B(OH)_2$ is completely neutralized against a strong acid,$10 \ kcal$ of heat is released. Calculate the enthalpy change when $1 \ mole$ of $H_2A$ is completely neutralized by $B(OH)_2$ in $kcal$.

$5 \, mol$ of an ideal gas at $100 \, K$ are allowed to undergo reversible compression till its temperature becomes $200 \, K$. If $C_v = 28 \, J \, K^{-1} \, mol^{-1}$,calculate $\Delta U$ and $\Delta pV$ for this process. $(R = 8.0 \, J \, K^{-1} \, mol^{-1})$

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 $.5$)

In a constant volume calorimeter,$3.5 \ g$ of a gas with molecular weight $28$ was burnt in excess oxygen at $298.0 \ K$. The temperature of the calorimeter was found to increase from $298.0 \ K$ to $298.45 \ K$ due to the combustion process. Given that the heat capacity of the calorimeter is $2.5 \ kJ \ K^{-1}$,the numerical value for the enthalpy of combustion of the gas in $kJ \ mol^{-1}$ is