How many liters of $H_2$ gas will be evolved at $STP$ by the reaction of zinc metal with $500 \, mL$ of $0.5 \, N \, HCl$?

Given that $N_{2(g)} + 3 H_{2(g)} \longrightarrow 2 NH_{3(g)}$; $\Delta_r H^{\circ} = -92 \ kJ$, the standard molar enthalpy of formation in $kJ \ mol^{-1}$ of $NH_{3(g)}$ is

What volume of $O_{2(g)}$ measured at standard condition will be formed by the action of $100 \ mL$ of $0.5 \ N \ KMnO_4$ on hydrogen peroxide in an acidic solution? The skeleton equation for the reaction is:
$KMnO_4 + H_2SO_4 + H_2O_2 \to KHSO_4 + MnSO_4 + O_2 + H_2O$
(Answer in $L$)

If a sample of $8.3 \ mL$ of $H_2SO_4$ $(36 \ N)$ is diluted with $991.7 \ mL$ of water,what is the approximate concentration of the resulting solution (in $N$)?

What amount of conc. $H_2SO_4$ solution should be used to prepare $500 \ mL$ of $0.5 \ M \ H_2SO_4$ (in $g$)? (The concentration of $H_2SO_4$ solution being used is $90\%$ and molecular mass of $H_2SO_4 = 98.079 \ g \ mol^{-1}$)

Calculate the volume of $H_2$ gas kept at $STP$ if it contains as many $H$ atoms as in $98 \ g$ of $H_3PO_4$. (Atomic mass of $P = 31 \ u$) (in $L$)