Which of the following processes entropy change $(\Delta S)$ is negative?

I. Sublimation of dry ice

II. Freezing of water

III. Crystallisation of the dissolved substance

IV. Burning of rocket fuel

Consider the following :

Statement I : During isothermal expansion of an ideal gas its enthalpy decreases.

Statement II : When 2.0 L of an ideal gas expands isothermally into vaccum, $\Delta U=0$.

The correct answer is :

The energy required to increase the temperature of 180 g of liquid water from $10^{\circ} \mathrm{C}$ to $15^{\circ} \mathrm{C}$ is 3765 J . What is $C_p$ of water in $\mathrm{J} \mathrm{mol}^{-1} \mathrm{~K}^{-1} ?\left(\mathrm{H}_2 \mathrm{O}=18 \mathrm{u}\right)$

At 273 K the maximum work done when pressure on 10 g of hydrogen is reduced from 10 atm to 1 atm under isothermal, reversible conditions is

(Assume the gas behaves ideally)

$$ \left(R=83 \mathrm{Jk}^{-1} \mathrm{~mol}^{-1}\right) $$