$CH_4 + \frac{1}{2}O_2 \to CH_3OH$ is an exothermic reaction $(\Delta H < 0)$. If the enthalpies of combustion of $CH_4$ and $CH_3OH$ are $x$ and $y$ respectively,which of the following relations is correct?

Given:
$2C + 2O_2 \to 2CO_2 : \Delta H = -787 \text{ kJ}$
$H_2 + \frac{1}{2}O_2 \to H_2O : \Delta H = -286 \text{ kJ}$
$C_2H_2 + \frac{5}{2}O_2 \to 2CO_2 + H_2O : \Delta H = -1310 \text{ kJ}$
Calculate the heat of formation of acetylene $(C_2H_2)$ in $\text{kJ}$.

Calculate the enthalpy change for the following reaction:
$H_2C=CH_{2(g)} + H_{2(g)} \longrightarrow H_3C-CH_{3(g)}$
[The bond energies of $C-H, C-C, C=C$ and $H-H$ are $414, 347, 615$ and $435 \ kJ/mol$ respectively.] (in $kJ$)

Which of the following reactions defines the standard enthalpy of combustion,$\Delta H_c^ \circ$?

$A$,$B$,$C$ and $D$ are some compounds. The enthalpy of formation of $A_{(g)}$,$B_{(g)}$,$C_{(g)}$ and $D_{(g)}$ is $9.7, -110, 81$ and $-393 \ kJ \ mol^{-1}$ respectively. What is $\Delta_r H$ (in $kJ \ mol^{-1}$) for the given reaction?
$A_{(g)} + 3B_{(g)} \longrightarrow C_{(g)} + 3D_{(g)}$

The heat of neutralization of a base with an acid is .......