Question

The aqueous solution of which of the following complex has the least conductivity under identical conditions.

• A. Penta aqua chlorido chromium (III) chloride
• B. Tetra aqua dichlorido chormium (III) chloride
• C. Hexa aqua chromium (III) chloride
• D. Tri aqua trichlorido chromium (III)

Answer 1

The correct option is D Tri aqua trichlorido chromium (III)

Lesser is the number of ions obtained in aqueous solution, lower is the electrical conductivity.

Tri aqua trichlorido chromium (III) $\left[Cr\right(H_{2}O{)}_{3}C{l}_3]$has the least conductivity under identical conditions.

This complex does not ionize in aqueous solution.
Penta aqua chlorido chromium (III) chloride $\left[Cr\right(H_{2}O{)}_{5}Cl]C{l}_2$ ionizes to give three ions in aqueous solution.

$\left[Cr\right(H_{2}O{)}_{5}Cl]C{l}_2\rightleftharpoons \left[Cr\right(H_{2}O{)}_{5}Cl{]}^{2+}+2C{l}^{-}$

Tetra aqua dichlorido chormium (III) chloride $\left[Cr\right(H_{2}O{)}_{4}C{l}_2]Cl$ ionizes to give two ions in aqueous solution.

$\left[Cr\right(H_{2}O{)}_{4}C{l}_2]Cl\rightleftharpoons [Cr(H_{2}O{)}_{4}C{l}_2{]}^{+}+C{l}^{-}$

Hexa aqua chromium (III) chloride $\left[Cr\right(H_{2}O{)}_6]C{l}_3$ ionizes to give four ions in aqueous solution.

$\left[Cr\right(H_{2}O{)}_6]C{l}_3\rightleftharpoons [Cr(H_{2}O{)}_6{]}^{3+}+3C{l}^{-}$