Question

$2.0$ g of a metallic carbonate on decomposition gives $1.5$ g of metallic oxide. The equivalent mass of the metal is:

• A. 58
• B. 29
• C. 5.8
• D. 2.9

Answer 1

The correct option is A 58

Since, the metal carbonate and metal oxide are involved in the same reaction, the ratio of their molecular weight will be equal to the ratio of their equivalent weight.

$\frac{\text{Weight of metal carbonate}}{\text{Weight of metallic oxide}}=\frac{\text{eq. mass of metal + eq. mass of}C{O}_3^{2-}}{\text{eq. mass of metal + eq. mass of}{O}^{2-}}$
Therefore, $\frac{2}{1.5}$ $=$ $\frac{x+30}{x+8}$.
On solving, we get $x$ $=$ $58$.