$A$ pure sample of water contains $88.89\%$ of oxygen by mass and $11.11\%$ of hydrogen by mass. This is an example of which law?

$1.0 \ g$ of an oxide of $A$ contained $0.5 \ g$ of $A$. $4.0 \ g$ of another oxide of $A$ contained $1.6 \ g$ of $A$. The data indicate the law of:

The law of definite proportions is not applicable to nitrogen oxides because

The following data are obtained when dinitrogen and dioxygen react together to form different compounds:

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 obeyed by the above experimental data? Give its statement.
$(b)$ Fill in the blanks in the following conversions:
$(i) \ 1 \ km = \dots \ mm = \dots \ pm$
$(ii) \ 1 \ mg = \dots \ kg = \dots \ ng$
$(iii) \ 1 \ mL = \dots \ L = \dots \ dm^{3}$

Two compounds are formed by carbon and oxygen. In one compound,the percentage of carbon is $42.9\%$ and in the other,the percentage of carbon is $27.3\%$. Which law of chemical combination is illustrated by this data?

$n \ g$ of substance $X$ reacts with $m \ g$ of substance $Y$ to form $p \ g$ of substance $R$ and $q \ g$ of substance $S$. This reaction can be represented as,$X + Y \rightarrow R + S$. The relation which can be established in the amounts of the reactants and the products will be