Which sample contains the largest number of atoms?

$K_2CS_3$ is called potassium ...... .

Match List-$I$ with List-$II$ and select the correct option (Based on mole concept):

List-$I$	List-$II$
$(a)$ $2 \text{ moles of ethene}$	$(i)$ $11.2 \text{ L volume at STP}$
$(b)$ $\text{Molar mass is equal to } 66 \text{ g}$	$(ii)$ $56 \text{ g}$
$(c)$ $1 \text{ g of } H_2$	$(iii)$ $12.04 \times 10^{23} \text{ molecules}$
$(d)$ $2 \text{ moles of water vapours}$	$(iv)$ $1.5 \text{ mole of } CO_2$

Hydrochloric acid solutions $A$ and $B$ have concentrations of $0.5 \ N$ and $0.1 \ N$ respectively. The volumes of solutions $A$ and $B$ required to make $2 \ L$ of $0.2 \ N$ $HCl$ are:

At $300 \ K$ temperature,$20 \ g \ H_2$,$220 \ g \ CO_2$,and $140 \ g \ N_2$ are filled in a vessel having volume $2 \ L$. Find the total pressure in $bar$ unit and which gas is removed from the vessel so that pressure can be reduced by $50 \%$. $(R = 8.34 \times 10^{-2} \ L \ bar \ K^{-1} \ mol^{-1})$

When a standard solution of $NaOH$ is left in air for a few hours: