For the reactions $(i) \, H_{2(g)} + Cl_{2(g)} \to 2HCl_{(g)} + x \, kJ$ and $(ii) \, H_{2(g)} + Cl_{2(g)} \to 2HCl_{(\ell)} + y \, kJ$,which of the following statements is correct?

Based on the bond enthalpy $(B.E.)$ values given,the standard enthalpy of formation $(\Delta_fH^o)$ of $N_2H_{4(g)}$ is ...... $kJ\ mol^{-1}$.
Given: $B.E.(N-N) = 159\ kJ\ mol^{-1}$,$B.E.(H-H) = 436\ kJ\ mol^{-1}$,$B.E.(N \equiv N) = 941\ kJ\ mol^{-1}$,$B.E.(N-H) = 398\ kJ\ mol^{-1}$.

$C_{(s)} + O_{2(g)} \rightarrow CO_{2(g)} \dots \dots(I) \quad \Delta H = -393 \, kJ \, mol^{-1}$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \rightarrow H_{2}O_{(l)} \dots \dots(II) \quad \Delta H = -287.3 \, kJ \, mol^{-1}$
$2CO_{2(g)} + 3H_{2}O_{(l)}$ $\rightarrow C_{2}H_{5}OH_{(l)} + 3O_{2(g)} \dots \dots(III) \quad \Delta H = 1366.8 \, kJ \, mol^{-1}$
Find the standard enthalpy of formation of $C_{2}H_{5}OH_{(l)}$.

The enthalpy of neutralisation of $NH_4OH$ with $HCl$ is $-51.46 \ kJ \ mol^{-1}$ and the enthalpy of neutralisation of $NaOH$ with $HCl$ is $-55.90 \ kJ \ mol^{-1}$. The enthalpy of ionisation of $NH_4OH$ is $...... \ kJ \ mol^{-1}$

The enthalpy of formation of ethane $(C_2H_6)$ from ethylene $(C_2H_4)$ by the addition of hydrogen,where the bond energies of $C-H$,$C-C$,$C=C$,and $H-H$ are $414 \ kJ/mol$,$347 \ kJ/mol$,$615 \ kJ/mol$,and $435 \ kJ/mol$ respectively,is $........$ $kJ/mol$.

The heat of neutralization of $HCl$ by $NaOH$ is $-57.3 \, kJ/mol$. If the heat of neutralization of $HCN$ by $NaOH$ is $-12.1 \, kJ/mol$,then the enthalpy of dissociation of $HCN$ is $...... \, kJ$.