Question

An excess of $AgN{O}_3$ is added to 100ml of 0.01 M solution of dichloridotetraaquachromium (III) chloride. The number of moles of AgCl precipitated would be

• A. 0.001
• B. 0.002
• C. 0.003
• D. 0.01

Answer 1

The correct option is A 0.001

The complex is $\left[Cr\right(H_{2}O\left)C{l}_2\right]Cl$
It ionizes as
$\left[Cr\right(H_{2}O{)}_{4}C{l}_2]Cl\rightleftharpoons [Cr(H_{2}O{)}_{4}C{l}_2{]}^{+}+C{l}^{-}$
1 mole 1 mole
Thus, 1 mole of the complex produces 1 mole of $C{l}^{-}$ ions and hence will precipitate out 1 mole of AgCl.100 ml of 0.01 M complex solutions contains moles of the complex.
$=\frac{0.01}{2}\times 100=0.001$ mole and will precipitate out 0.001 mole of AgCl