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 $, mL$)?

$A$ mixture of hydrogen and oxygen contains $20\%$ by weight of hydrogen. Find the total number of molecules per gram of the mixture.

Dinitrogen and dioxygen react with each other to form different compounds. The experimental data is given below:

Mass of Dinitrogen	Mass of Dioxygen
$(i) \ 14 \ g$	$16 \ g$
$(ii) \ 14 \ g$	$32 \ g$
$(iii) \ 28 \ g$	$32 \ g$
$(iv) \ 28 \ g$	$80 \ g$

$(a)$ Which law of chemical combination is followed by the above experimental data? State the law.
$(b)$ Fill in the blanks in the following conversions:
$(i) \ 1 \ km = \dots \ mm = \dots \ pm$
$(ii) \ 1 \ mg = \dots \ kg = \dots \ ng$
$(iii) \ 1 \ mL = \dots \ L = \dots \ dm^3$

$10 \ mL$ of $2 \ M$ $NaOH$ solution is added to $20 \ mL$ of $1 \ M$ $HCl$ solution kept in a beaker. Now,$10 \ mL$ of this mixture is poured into a volumetric flask of $100 \ mL$ containing $2 \ moles$ of $HCl$ and made the volume up to the mark with distilled water. The solution in this flask is $:$

How is concentrated $H_2SO_4$ diluted?

Density of a $2.05 \ M$ solution of $H_2SO_4$ in water is $1.08 \ g/mL$. Find its Normality and molality.