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

In the reaction $C + 2S \to CS_2 + \Delta H$,$\Delta H$ is the

The bond energies of $C-C$,$C=C$,$H-H$,and $C-H$ bonds are $350$,$600$,$400$,and $410 \ kJ \cdot mol^{-1}$ respectively. The heat of hydrogenation of ethylene $(C_2H_4)$ is ... $kJ \cdot mol^{-1}$.

The enthalpy of atomization of $PH_3(g)$ is $228 \, kcal \, mol^{-1}$ and that of $P_2H_4(g)$ is $355 \, kcal \, mol^{-1}$. The $P-P$ bond energy (in $kcal \, mol^{-1}$) is:

Given the bond energies of $N \equiv N$,$H - H$ and $N - H$ bonds are $945$,$436$ and $391 \ kJ \cdot mol^{-1}$ respectively,the enthalpy of the following reaction $N_{2(g)} + 3H_{2(g)} \to 2NH_{3(g)}$ is ...... $kJ$.

Considering the reaction $3O_2 \rightarrow 2O_3$; $\Delta H = +ve$,what can we conclude about the reaction?