Question

The oxide of a metal contains $60$% of the metal. What will be the approximate percentage of bromine in the bromide of the metal, if the valency of the metal is same in both the oxide and the bromide?

• A. $87$
• B. $70$
• C. $77$
• D. $93$

Answer 1

The correct option is A $87$

The metal oxide contains $60$% metal and $40$% oxygen.
Equivalent weight of oxygen is $8$.
Let the equivalent weight of metal be $E$.
Hence, eq. of metal = eq. of oxygen.
$\frac{60}{E}=\frac{40}{8},E=12$.
Let $a$ be the percentage of bromine in metal bromide.
Equivalent weight of bromine is $80$.
$\frac{100-a}{12}=\frac{a}{80},a\cong 87$