How many moles of $KCl$ are dissolved in $1000 \ mL$ of $3 \ M$ $KCl$ solution?

$28 \ g$ $KOH$ is required to completely neutralize $CO_2$ produced on heating $60 \ g$ of impure $CaCO_3$. The percentage purity of $CaCO_3$ is approximately (molar masses of $KOH$ and $CaCO_3$ are $56$ and $100 \ g \ mol^{-1}$,respectively).

How many moles of methane are required to produce $22 \ g$ of $CO_2 \ (g)$ after combustion (in $mol$)?

The amount of calcium oxide produced on heating $150 \ kg$ of limestone ($75 \%$ pure) is $........... \ kg$ $(Nearest \ integer)$. Given: Molar mass (in $g \ mol^{-1}$) of $Ca = 40, O = 16, C = 12$.

To $50 \ mL$ of $0.1 \ N \ Na_2CO_3$ solution,$150 \ mL$ of water is added. What is the molarity of the resultant solution?

At $NTP$,$40 \, mL$ of nitrogen reacts with hydrogen to form ammonia. According to the reaction $N_2 + 3H_2 \rightarrow 2NH_3$,the mass of ammonia formed will be ..... (in $, g$)