Among the following pairs of compounds,the one that illustrates the law of multiple proportions is

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:
$(i) \ 1 \ km = \dots \ mm = \dots \ pm$
$(ii) \ 1 \ mg = \dots \ kg = \dots \ ng$
$(iii) \ 1 \ mL = \dots \ L = \dots \ dm^{3}$

State and explain Gay-Lussac's Law of Gaseous Volumes.

Which of the following statements is correct about the given reaction?
$4Fe_{(s)} + 3O_{2_{(g)}} \to 2Fe_{2}O_{3_{(s)}}$

Two elements $x$ and $y$ have atomic masses $14$ and $16$ respectively. They form a series of five compounds $A, B, C, D, E$ in which the ratio of $x$ to $y$ is $1:2:3:4:5$. If compound $A$ contains $28$ parts by weight of $x$ and $16$ parts by weight of $y$,then in compound $C$,how many parts by weight of $x$ will combine with $24$ parts by weight of $y$?

Hydrogen peroxide and water contain $5.93\%$ and $11.2\%$ of hydrogen,respectively. Which law is illustrated by this data?