$$\mathrm{Fe}^{3+}$$ cation gives a prussian blue precipitate on addition of potassium ferrocyanide solution due to the formation of :

The normality of $$\mathrm{H}_{2} \mathrm{SO}_{4}$$ in the solution obtained on mixing $$100 \mathrm{~mL}$$ of $$0.1 \,\mathrm{M} \,\mathrm{H}_{2} \mathrm{SO}_{4}$$ with $$50 \mathrm{~mL}$$ of $$0.1 \,\mathrm{M}\, \mathrm{NaOH}$$ is _______________ $$\times 10^{-1} \mathrm{~N}$$. (Nearest Integer)

A gas (Molar mass = 280 $$\mathrm{~g} \mathrm{~mol}^{-1}$$) was burnt in excess $$\mathrm{O}_{2}$$ in a constant volume calorimeter and during combustion the temperature of calorimeter increased from $$298.0 \mathrm{~K}$$ to $$298.45$$ $$\mathrm{K}$$. If the heat capacity of calorimeter is $$2.5 \mathrm{~kJ} \mathrm{~K}^{-1}$$ and enthalpy of combustion of gas is $$9 \mathrm{~kJ} \mathrm{~mol}^{-1}$$ then amount of gas burnt is _____________ g. (Nearest Integer)

When a certain amount of solid A is dissolved in $$100 \mathrm{~g}$$ of water at $$25^{\circ} \mathrm{C}$$ to make a dilute solution, the vapour pressure of the solution is reduced to one-half of that of pure water. The vapour pressure of pure water is $$23.76 \,\mathrm{mmHg}$$. The number of moles of solute A added is _____________. (Nearest Integer)