A 1.84 mg sample of polyhydric alcoholic compound 'X' of molar mass 92.0 g/mol gave 1.344 mL of $$\mathrm{H}_{2}$$ gas at STP. The number of alcoholic hydrogens present in compound 'X' is ________.

2L of 0.2M H₂SO₄ is reacted with 2L of 0.1M NaOH solution, the molarity of the resulting product Na₂SO₄ in the solution is _________ millimolar. (Nearest integer)

In the given reaction,

$$X+Y+3 Z \leftrightarrows X YZ_{3}$$

if one mole of each of $$X$$ and $$Y$$ with $$0.05 \mathrm{~mol}$$ of $$Z$$ gives compound $$X Y Z_{3}$$. (Given : Atomic masses of $$X, Y$$ and $$Z$$ are 10, 20 and 30 amu, respectively.) The yield of $$X YZ_{3}$$ is _____________ g. (Nearest integer)

On complete combustion of $$0.492 \mathrm{~g}$$ of an organic compound containing $$\mathrm{C}, \mathrm{H}$$ and $$\mathrm{O}$$, $$0.7938 \mathrm{~g}$$ of $$\mathrm{CO}_{2}$$ and $$0.4428 \mathrm{~g}$$ of $$\mathrm{H}_{2} \mathrm{O}$$ was produced. The % composition of oxygen in the compound is ___________.