The energy of combustion per mole of $H_2$,$LPG$,and octane follows the order:

$36 \, mL$ of pure water takes $100 \, sec$ to evaporate from a vessel and heater connected to an electric source which delivers $806 \, watt$. The $\Delta H_{\text{vaporization}}$ of $H_2O$ is $... \, kJ/mol$

The heat of combustion of naphthalene $(C_{10}H_8(s))$ at constant volume is $-5133 \, kJ \, mol^{-1}$. The value of enthalpy change is .... $J$ $(R = 8.314 \, J \, K^{-1} \, mol^{-1}, T = 298 \, K)$.

$2 \ mol$ of $Hg_{(g)}$ is combusted in a fixed volume bomb calorimeter with excess of $O_2$ at $298 \ K$ and $1 \ atm$ into $HgO_{(s)}$. During the reaction,temperature increases from $298.0 \ K$ to $312.8 \ K$. If heat capacity of the bomb calorimeter and enthalpy of formation of $Hg_{(g)}$ are $20.00 \ kJ \ K^{-1}$ and $61.32 \ kJ \ mol^{-1}$ at $298 \ K$,respectively,the calculated standard molar enthalpy of formation of $HgO_{(s)}$ at $298 \ K$ is $X \ kJ \ mol^{-1}$. The value of $|X|$ is. . . . . [Given : Gas constant $R = 8.3 \ J \ K^{-1} \ mol^{-1}$]

Which one of the following is always not negative?

Identify the correct statement$(s)$: