Question

Which of the following statements illustrates the law of multiple proportions?

• A. An element forms two oxides, $XO$ and $X{O}_2$ containing $50\%$ and $60\%$ oxygen respectively. The ratio of masses of oxygen which combines with $1g$ of element is $2:3$
• B. Hydrogen sulphide contains $5.89\%$ hydrogen, water contains $11.1\%$ hydrogen and sulphur dioxide contains $50\%$ oxygen
• C. $3.47g$ of $BaC{l}_2$ reacts with $2.36g$ of $N{a}_{2}S{O}_4$ to give $3.88g$ of $BaS{O}_4$ and $1.95g$ of $NaCl$
• D. $20mL$ of ammonia gives $10$ volumes of $N_2$ and $30$ volumes of $H_2$ at constant temperature and pressure

Answer 1

Answer: (A)

In $XO,50g$ of element combines with $50g$ of oxygen.
$\therefore 1g$ of element combines with $1g$ of oxygen.
In $X{O}_2,40g$ of element combines with $60g$ of oxygen.
$\therefore 1g$ of element combines with $1.5g$ of oxygen.
Thus, ratio of masses of oxygen which combines with $1g$ of element is $1:1.5$ or $2:3$. This is in accordance with the law of multiple proportions. In $(b)$ the law of reciprocal proportions is followed. In $(c)$ law of conservation of mass is followed while in $(d)$ Avogadros law is followed.