An electric heater of power $600 \, W$ takes $8 \, \text{minutes}$ to evaporate $80 \, mL$ of water. The enthalpy of vaporization of water is ......... $kJ \, mol^{-1}$.

Enthalpy of formation of $HF$ and $HCl$ are $-161 \ kJ$ and $-92 \ kJ$ respectively. Which of the following statements is incorrect?

When $128 \, g$ of oxygen gas is heated from $0 \, ^oC$ to $100 \, ^oC$,the average values of $C_v$ and $C_p$ are $5 \, cal \, mol^{-1} \, K^{-1}$ and $7 \, cal \, mol^{-1} \, K^{-1}$ respectively. Find the values of $\Delta U$ and $\Delta H$.

$5 \, mol$ of an ideal gas at $100 \, K$ are allowed to undergo reversible compression till its temperature becomes $200 \, K$. If $C_v = 28 \, J \, K^{-1} \, mol^{-1}$,calculate $\Delta U$ and $\Delta pV$ for this process. $(R = 8.0 \, J \, K^{-1} \, mol^{-1})$

The volume of a gas decreases from $500 \ cc$ to $300 \ cc$ when a sample of gas is compressed by an average pressure of $0.6 \ atm$. During this process $10 \ J$ of heat is liberated. The change in internal energy is......$J$

$\Delta H^o_f$ of water is $-285.5 \, kJ \, mol^{-1}$. If enthalpy of neutralisation of monoacidic strong base is $-57.3 \, kJ \, mol^{-1}$,$\Delta H^o_f$ of $OH^{-}$ ion will be.....$kJ \, mol^{-1}$