When $30 \ mL$ of $H_2$ reacts with $20 \ mL$ of $O_2$ to form water,what is leftover when the reaction ends?

According to the reaction $2A + B \to C$,$8 \ mol$ of $A$ and $5 \ mol$ of $B$ will produce how many moles of $C$?

When $35 \ mL$ of $0.15 \ M$ lead nitrate solution is mixed with $20 \ mL$ of $0.12 \ M$ chromic sulphate solution,$....... \times 10^{-5}$ moles of lead sulphate precipitate out. (Round off to the Nearest Integer).

Assume carbon burns according to the following equation:
$2C_{(s)} + O_{2(g)} \rightarrow 2CO_{(g)}$
When $12 \ g$ of carbon is burnt in $48 \ g$ of oxygen,the volume of carbon monoxide produced is $...... \times 10^{-1} \ L$ at $STP$ [nearest integer].
[Given: Assume $CO$ as an ideal gas,molar mass of $C = 12 \ g \ mol^{-1}$,molar mass of $O = 16 \ g \ mol^{-1}$,and molar volume of an ideal gas at $STP$ = $22.7 \ L \ mol^{-1}$]

One mole of $Cl_{2(g)}$ was passed into $2 \text{ L}$ of cold $2 \text{ M}$ $KOH$ solution. After the reaction, the concentrations of $Cl^{-}$, $ClO^{-}$ and $OH^{-}$ are respectively (assume volume remains constant):

Under similar conditions of pressure and temperature,$40 \, mL$ of slightly moist hydrogen chloride gas is mixed with $20 \, mL$ of ammonia gas,the final volume of gas at the same temperature and pressure will be ............. $mL$.