Question

The total ionic strength of the solution containing $0.1$ M of $CuS{O}_4$ and $0.1$ M of ${Al}_2{\left(S{O}_4\right)}_3$ is :

• A. 0.2 M
• B. 0.19 M
• C. 0.8 M
• D. 0.105 M

Answer 1

Answer: (B)

0.19 M

In solution,
$CuS{O}_4\to C{u}^{+2}+S{O}_4^{-2}$
0.1 0.1 0.1
$A{l}_2(S{O}_4{)}_3\to 2A{l}^{+3}+3S{O}_4^{-2}$
0.1 0.2 0.3
Total ionic strength = $\frac{1}{2}\Sigma c{Z}^2$
=$\frac{1}{2}[0.1\times 2^2+0.1\times 2^2+0.1\times 2\times 3^2+0.1\times 3\times 2^2]=0.19$