The number of moles of hydrogen molecules required to produce $20$ moles of ammonia through Haber's process is

The molarity of a solution made by mixing $50 \ mL$ of conc. $H_2SO_4$ $(36 \ N)$ with $50 \ mL$ of water is ...... $M$.

Magnetite can be reduced with $CO$ to yield iron metal and carbon dioxide. Calculate the mass of magnetite (in $kg$) needed to obtain $4 \ kg$ of iron if the process is $80 \%$ efficient. [Atomic weight of $Fe$ and $O$ are $56 \ g$ and $16 \ g$, respectively]

To obtain the maximum mass of $NO_2$ from a given mass of a mixture of $NH_3$ and $O_2$,the ratio of the mass of $NH_3$ to $O_2$ should be based on the reaction: $NH_3 + O_2 \longrightarrow NO_2 + H_2O$

What is the mass of $33.6 \ dm^3$ of methane gas at $S.T.P.$?

How many liters of $CO_2$ gas are released at $STP$ upon the complete decomposition of $9.85 \ g$ of $BaCO_3$ (Atomic mass of $Ba = 137$)?