How much $H_2$ gas (in $L$) will be produced at $STP$ when $27 \ g$ of aluminum reacts with aqueous $NaOH$?

How much heat change in $kJ$ will occur when $233.0 \, g$ of calcium oxide reacts with sufficient carbon to produce $CaC_2$? The reaction is: $CaO_{(s)} + 3C_{(s)} \to CaC_{2(s)} + CO_{(g)}$; $\Delta H^o = 464.8 \, kJ/mol$.

If Avogadro's number is $A_0$,the number of sulphur atoms present in $200 \, mL$ of $1 \, N \, H_2SO_4$ is

Aqueous $HCl$ reacts with $MnO_{2(s)}$ to form $MnCl_{2(aq)}$, $Cl_{2(g)}$ and $H_{2}O_{(l)}$. What is the weight (in $g$) of $Cl_{2}$ liberated when $8.7 \ g$ of $MnO_{2(s)}$ is reacted with excess aqueous $HCl$ solution? (Given Molar mass in $g \ mol^{-1}$: $Mn=55$, $Cl=35.5$, $O=16$, $H=1$)

$A$ metal exists as an oxide with formula $M_{0.96} O$. Metal $M$ can exist as $M^{2+}$ and $M^{3+}$ in its oxide $M_{0.96} O$. The percentage of $M^{3+}$ in the oxide is nearly: (in $\%$)

What volume of Hydrogen gas,at $273 \ K$ and $1 \ atm$ pressure,will be consumed in obtaining $21.6 \ g$ of elemental boron (atomic mass $= 10.8$) from the reduction of boron trichloride by Hydrogen? (Answer in $L$)