The density of an equimolar mixture of $CH_4$ and $CO$ at $STP$ is ............... $g \, L^{-1}$.

Bleaching powder and bleach solution are produced on a large scale and used in several household products.
The effectiveness of bleach solution is often measured by iodometry.
$1.$ $25 \ mL$ of household bleach solution was mixed with $30 \ mL$ of $0.50 \ M \ KI$ and $10 \ mL$ of $4 \ N$ acetic acid. In the titration of the liberated iodine,$48 \ mL$ of $0.25 \ N \ Na_2S_2O_3$ was used to reach the end point. The molarity of the household bleach solution is
$(A)$ $0.48 \ M$ $(B)$ $0.96 \ M$ $(C)$ $0.24 \ M$ $(D)$ $0.024 \ M$
$2.$ Bleaching powder contains a salt of an oxoacid as one of its components. The anhydride of that oxoacid is
$(A)$ $Cl_2O$ $(B)$ $Cl_2O_7$ $(C)$ $ClO_2$ $(D)$ $Cl_2O_6$
Give the answer for question $1$ and $2.$

The normality of $H_{2}SO_{4}$ in the solution obtained on mixing $100 \ mL$ of $0.1 \ M \ H_{2}SO_{4}$ with $50 \ mL$ of $0.1 \ M \ NaOH$ is $\times 10^{-1} \ N$. (Nearest Integer)

Rearrange the following ($I$ to $IV$) in the order of increasing masses:
$(I)$ $0.5$ mole of $O_3$
$(II)$ $0.5 \, g$ atom of oxygen
$(III)$ $3.011 \times 10^{23}$ molecules of $O_2$
$(IV)$ $5.6 \, L$ of $CO_2$ at $STP$

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: