Question

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

• A. An element forms two oxides, $XO$ and $XO_2$ containing $50\%$ and $60\%$ oxygen respectively. The ratio of masses of oxygen which combines with $1\, g$ of element is $2 : 3$
• B. Hydrogen sulphide contains $5.89\%$ hydrogen, water contains $11.1\%$ hydrogen and sulphur dioxide contains $50\%$ oxygen
• C. $3.47\, g $ of $BaCl_2$ reacts with $2.36\, g$ of $Na_2SO_4$ to give $3.88 \,g$ of $BaSO_4$ and $1.95\, g$ of $NaCl$
• D. $20 \,mL$ of ammonia gives $10$ volumes of $N_2$ and $30$ volumes of $H_2$ at constant temperature and pressure

Answer 1

Answer: (A)

In $XO, 50 \,g$ of element combines with $50\, g$ of oxygen.
$ \therefore 1\, g$ of element combines with $1 \,g$ of oxygen.
In $XO_2,40\, g$ of element combines with $60\, g$ of oxygen.
$\therefore 1 \,g$ of element combines with $1.5\, g$ of oxygen.
Thus, ratio of masses of oxygen which combines with $1 \,g$ 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.