Question

A $2.8g$ of mixture of carbonates of two monovalent metals are heated to corresponding oxides and carbondioixde. The metal $A$ is $20\%$ by weight. The mass of carbondioxide obtained from the reaction is $0.88g$. The mass of the metal $B$ in the mixture is

• A. $2.08g$
• B. $0.56g$
• C. $1.04g$
• D. $1.2g$

Answer 1

The correct option is C $1.04g$

$A_{2}C{O}_3\to A_{2}O+C{O}_2$
$B_{2}C{O}_3\to B_{2}O+C{O}_2$

$\text{Metal A is 20 percent by weight}$.

$\text{Mass of the metal A =}2.8\times \frac{20}{100}=0.56g$

$\text{Moles of the}C{O}_3=\text{moles of}C{O}_2$

$\text{Moles of}C{O}_2=\frac{0.88}{44}=0.02$
$\text{Mass of}C{O}_3=0.02\times 60=1.2$
$\text{Mass of the metal B}=2.8-0.56-1.2=1.04g$