Given that the molar combustion enthalpies of benzene,cyclohexane,and hydrogen are $x, y$,and $z$ respectively,the molar enthalpy of hydrogenation of benzene to cyclohexane is

For the reaction $F_2 + 2HCl \rightarrow 2HF + Cl_2$,the $\Delta H^o$ is $-352.8 \ kJ$. If the $\Delta H_f^o$ for $HF$ is $-268.3 \ kJ \ mol^{-1}$,then the $\Delta H_f^o$ for $HCl$ will be . . . . . . $kJ \ mol^{-1}$.

Find the enthalpy of formation of the $OH^-$ ion in $KJ$ at $25^\circ C$ from the following data:
$H_2O_{(l)} \to H^+_{(aq)} + OH^-_{(aq)} ; \Delta H = 57.32 \ KJ$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \to H_2O_{(l)} ; \Delta H = -286.20 \ KJ$

On the basis of the following equations,the heat of dimerisation of $NO_2$ will be:
$(i) \ N_2 + 2O_2 \to 2NO_2, \Delta H = 67.9 \ kJ$
$(ii) \ N_2 + 2O_2 \to N_2O_4, \Delta H = 9.3 \ kJ$

Calculate the enthalpy of formation of nitric oxide $(NO)$ in $kJ \, mol^{-1}$ from the following data:
$NO_{(g)} + CO_{(g)} \rightarrow \frac{1}{2} N_{2(g)} + CO_{2(g)}; \Delta H^o = -372.2 \, kJ \, mol^{-1}$
$\Delta H_f^o (CO) = -110.5 \, kJ \, mol^{-1}$
$\Delta H_f^o (CO_2) = -393.5 \, kJ \, mol^{-1}$

The molar neutralization heat for $KOH$ and $HNO_3$ as compared to the molar neutralization heat of $NaOH$ and $HCl$ is: