$$20 \mathrm{~mL}$$ of calcium hydroxide was consumed when it was reacted with $$10 \mathrm{~mL}$$ of unknown solution of $$\mathrm{H}_{2} \mathrm{SO}_{4}$$. Also $$20 \mathrm{~mL}$$ standard solution of $$0.5 ~\mathrm{M} ~\mathrm{HCl}$$ containing 2 drops of phenolphthalein was titrated with calcium hydroxide, the mixture showed pink colour when burette displayed the value of $$35.5 \mathrm{~mL}$$ whereas the burette showed $$25.5 \mathrm{~mL}$$ initially. The concentration of $$\mathrm{H}_{2} \mathrm{SO}_{4}$$ is _____________ M. (Nearest integer)

The volume of hydrogen liberated at STP by treating $$2.4 \mathrm{~g}$$ of magnesium with excess of hydrochloric acid is _________ $$\times ~10^{-2} \mathrm{~L}$$

Given : Molar volume of gas is $$22.4 \mathrm{~L}$$ at STP.

Molar mass of magnesium is $$24 \mathrm{~g} \mathrm{~mol}^{-1}$$

A solution of sugar is obtained by mixing $$200 \mathrm{~g}$$ of its $$25 \%$$ solution and $$500 \mathrm{~g}$$ of its $$40 \%$$ solution (both by mass). The mass percentage of the resulting sugar solution is ___________ (Nearest integer)

$$0.5 \mathrm{~g}$$ of an organic compound $$(\mathrm{X})$$ with $$60 \%$$ carbon will produce __________ $$\times 10^{-1} \mathrm{~g}$$ of $$\mathrm{CO}_{2}$$ on complete combustion.