Question

When 4.215 g of a metallic carbonate was heated in a hard glass tube, the $C{O}_2$ evolved was found to measure 1336 mL at ${27}^{\circ }C$ and 700 mm pressure. The equivalent weight of the metal(only integer part) is _______.

Answer 1

From Ideal gas law,

$PV=nRT=\frac{w}{M}RT$

or $\frac{700}{760}\times \frac{1336}{1000}=\frac{w}{44}\times 0.0821\times 300$

or $w=2.198gC{O}_2$

Molecular mass of any metal carbonate($M_{2}C{O}_3$) is $2E+60$, where $E$ is the equivalent mass of the metal.

$\frac{2E+60}{4.215}=\frac{44}{2.198}$

or $E=12.188g$

$\simeq 12$