Question

The carbonate of a metal is isomorphous (similar formula) with magnesium carbonate and contains 6.091 percent of carbon. The atomic weight of metal is:

• A. 24
• B. 56
• C. 137
• D. 260

Answer 1

The correct option is C 137

Let the formula of unknown carbonate= $XC{O}_3$

Molecular weight= $x+12+48=(60+x)gmo{l}^{-1}$

% of composition of carbon= $\left[\frac{12}{(60+x)}\right]\times 100$

$\Rightarrow 6.091=\frac{12}{60+x}\times 100$

$\Rightarrow 0.06091(60+x)=12$

$\Rightarrow x=137.01$

$\therefore$ The atomic weight of metal is $137g/mol$.

Hence, option $C$ is correct.