Question

Common salt obtained from Clifton beach contained $60.75\%$ chlorine while $6.40$ g of a sample of common salt from Khewra mine contained $3.888$ g of chlorine. State the law illustrated by these chemical combinations.

• A. Law of reciprocal proportion
• B. Law of multiple proportion
• C. Law of constant composition
• D. None of the above

Answer 1

Answer: (C)

Law of constant composition

First case :

Common salt from Clifton beach contains $=$ $60.75\%$ $C{l}_2$

$100$ g of salt $=60.75$ g of $C{l}_2$

$1$ g of salt $=\frac{60.75}{100}=0.6075$ g of $C{l}_2$

Second case :

$6.40$ g of $NaCl$ from Khewra mine $=3.888$ g of $C{l}_2$

$1$ g of $NaCl$ from Khewra mine $=\frac{3.888}{6.40}=0.6075$ g of $C{l}_2$

Thus, the weight of $C{l}_2$ in $1$ g of salt in both the cases is same. Hence, the law of constant composition is verified.

Hence the correct option is C.