If the density of methanol is $0.793 \, kg \, L^{-1}$,what is its volume needed for making $2.5 \, L$ of its $0.25 \, M$ solution (in $, mL$)?

$50 \ mL$ of $10 \ N \ H_2SO_4$,$25 \ mL$ of $12 \ N \ HCl$,and $40 \ mL$ of $5 \ N \ HNO_3$ were mixed together,and the volume of the mixture was made $1000 \ mL$ by adding water. The normality of the resultant solution will be.....$N$.

The more commonly used baking powder contains about $30\%$ $NaHCO_3$,$20\%$ $NaAl(SO_4)_2$,$10\%$ $Ca(H_2PO_4)_2$ and $40\%$ starch. Which of the following statements is/are correct?

Mohr's salt is

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

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

Mole fraction of $O_2$ in $O_2$ and $O_3$ mixture is $0.25$. Hence percentage concentration $\left( \frac{w}{W} \% \right)$ of $O_2$ in the mixture is: