Observe the following reaction:
$2 A_{2(g)} + B_{2(g)} \xrightarrow{T(K)} 2 A_2 B_{(g)} + 600 \ kJ$
The standard enthalpy of formation $(\Delta_f H^{\circ})$ of $A_2 B_{(g)}$ is:

The enthalpy of neutralisation of $NH_4OH$ and $HCl$ is numerically:

Given the following thermochemical equations:
$(1) \ S + O_2 \rightarrow SO_2 ; \Delta H = -298.2 \ kJ$
$(2) \ SO_2 + \frac{1}{2} O_2 \rightarrow SO_3 ; \Delta H = -98.7 \ kJ$
$(3) \ SO_3 + H_2O \rightarrow H_2SO_4 ; \Delta H = -130.2 \ kJ$
$(4) \ H_2 + \frac{1}{2} O_2 \rightarrow H_2O ; \Delta H = -287.3 \ kJ$
Calculate the enthalpy of formation of $H_2SO_4$ at $298 \ K$ in $kJ$.

Given that $Fe + 1/2 O_2 \to FeO + x \, kcal$ and $2FeO + 1/2 O_2 \to Fe_2O_3 + y \, kcal$,the heat of formation of $Fe_2O_3$ from $Fe$ and oxygen will be ...

The standard enthalpy of formation,$\Delta H_f^o$,for an explosive substance like $NCl_3$ will be ......

The heats of formation of two compounds $X$ and $Y$ are $-84 \ kJ$ and $-156 \ kJ$ respectively. Which of the following statements is correct?