The statement related to the law of definite proportions is:

Gay-Lussac's law of gaseous volumes is derived from $.......$.

To check the principle of multiple proportions,a series of pure binary compounds $(P_m Q_n)$ were analyzed and their composition is tabulated below. The correct option$(s)$ is(are)

Compound	Weight $\%$ of $P$	Weight $\%$ of $Q$
$1$	$50$	$50$
$2$	$44.4$	$55.6$
$3$	$40$	$60$

$(A)$ If empirical formula of compound $3$ is $P_3 Q_4$,then the empirical formula of compound $2$ is $P_3 Q_5$.
$(B)$ If empirical formula of compound $3$ is $P_3 Q_2$ and atomic weight of element $P$ is $20$,then the atomic weight of $Q$ is $45$.
$(C)$ If empirical formula of compound $2$ is $PQ$,then the empirical formula of the compound $1$ is $P_5 Q_4$.
$(D)$ If atomic weight of $P$ and $Q$ are $70$ and $35$,respectively,then the empirical formula of compound $1$ is $P_2 Q$.

Atoms combine in chemical reactions to form:

Which of the following pairs of substances illustrates the Law of Multiple Proportions?

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 $y$?