What is the volume (in litres) of oxygen required at $STP$ to completely convert $1.5 \ mol$ of sulphur into sulphur dioxide?

$0.7 \ g$ of $Na_2CO_3 \cdot xH_2O$ were dissolved in water and the volume was made to $100 \ mL$. $20 \ mL$ of this solution required $19.8 \ mL$ of $N/10 \ HCl$ for complete neutralization. The value of $x$ is:

One mole of fluorine is reacted with two moles of hot concentrated $KOH$. The products formed are $KF, H_2O$ and $O_2$. The molar ratio of $KF, H_2O$ and $O_2$, respectively is

$20.0 \ g$ of a magnesium carbonate sample decomposes on heating to give carbon dioxide and $8.0 \ g$ magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? $(At. \ wt. \ of \ Mg = 24)$

The molecular weight of a gas is $45$. Its density at $STP$ is

What is the quantity of hydrogen gas liberated when $46 \ g$ sodium reacts with excess ethanol? (Given Atomic mass of $Na = 23$)