The right option for the mass of $CO_2$ produced by heating $20 \ g$ of $20 \%$ pure limestone is $........ \ g$ (Atomic mass of $Ca = 40$) $[CaCO_3 \stackrel{1200 \ K}{\longrightarrow} CaO + CO_2]$

In the reaction $2 KClO_{3(s)} \longrightarrow 2 KCl_{(s)} + 3 O_{2(g)}$,$\Delta H^{\circ} = -78 \ kJ$. If $33.6 \ L$ of oxygen gas is liberated at $S.T.P.$,what is the mass of $KCl_{(s)}$ produced (in $g$)? (Atomic mass: $K = 39, Cl = 35.5 \ g \ mol^{-1}$)

$X \ g$ of nitrobenzene on nitration gave $4.2 \ g$ of $m-$dinitrobenzene. $X = ............ \ g$. $(nearest \ integer)$ [Given: molar mass (in $g \ mol^{-1}$) $C: 12, H: 1, O: 16, N: 14$]

$5 \, N$ $H_2SO_4$ was diluted from $1 \, L$ to $10 \, L$. The normality of the solution obtained is.....$N$.

$100 \ mL$ of $H_{2(g)}$ and $100 \ mL$ of $Cl_{2(g)}$ were allowed to react at $1 \ bar$ pressure as: $H_{2(g)} + Cl_{2(g)} \longrightarrow 2 HCl_{(g)}$. What will be the $PV$ type of work done during the reaction?

What will be the normality of the salt solution obtained by neutralising $x \ mL$ $y \ (N)$ $HCl$ with $y \ mL$ $x \ (N)$ $NaOH$, and finally adding $(x+y) \ mL$ distilled water?