How many $mL$ of $1 \, M$ $H_2SO_4$ is required to neutralize $10 \, mL$ of $1 \, M$ $NaOH$ solution?

$40\%$ of a mixture of $0.2 \ mol$ of $N_2$ and $0.6 \ mol$ of $H_2$ reacts to give $NH_3$ according to the equation:
$N_{2(g)} + 3H_{2(g)} \rightleftharpoons 2NH_{3(g)}$
at constant temperature and pressure. What is the ratio of the final volume to the initial volume of gases?

How much volume of $1 \,N$ aqueous solution of $H_2SO_4$ should be taken, which will contain $0.2$ moles of $H_2SO_4$ (in $\,mL$)?

The ratio of the molar amounts of $H_2S$ needed to precipitate the metal ions from $20 \ mL$ each of $1 \ M \ Cd(NO_3)_2$ and $0.5 \ M \ CuSO_4$ is

$1.0 \ g$ of pure calcium carbonate was found to require $50 \ mL$ of dilute $HCl$ for complete reaction. The strength of the $HCl$ solution is given by ........ $N$.

$A$ sample of a metal oxide has the formula $M_{0.83}O_{1.00}$. The metal $M$ can exist in two oxidation states,$+2$ and $+3$. In the sample of $M_{0.83}O_{1.00}$,the percentage of metal ions existing in the $+2$ oxidation state is $.........\%$ (nearest integer).