How many moles of ammonia are produced by $5$ moles of hydrogen (in $.3$)?

Calculate the approximate mass (in $g$) of $H_2S$ required for the following reaction when $15 \ L$ of oxygen at $STP$ reacts completely.
$2 H_2S_{(g)} + 3 O_{2(g)} \longrightarrow 2 SO_{2(g)} + 2 H_2O_{(g)}$
(molar mass of $H_2S = 34 \ g \ mol^{-1}$)

The amount of calcium oxide produced on heating $150 \ kg$ of limestone ($75 \%$ pure) is $........... \ kg$ $(Nearest \ integer)$. Given: Molar mass (in $g \ mol^{-1}$) of $Ca = 40, O = 16, C = 12$.

What will be the weight of lime $(CaO)$ obtained by heating $300 \ kg$ of $90\%$ pure limestone $(CaCO_3)$?

How many millimoles of $H^{+}$ ions are present in $100 \, mL$ of $0.6 \, N \, H_3PO_4$?

When the same amount of zinc is treated separately with an excess of sulphuric acid and an excess of sodium hydroxide solution,the ratio of the volumes of hydrogen evolved is: