A complex is represented as CoCl3- XNH3- Its 0-1 molal solution in water shows - Tf-0-558oC- Kf of H2O is 1-86 K-m- Assuming 100

The expression for the depression in the freezing point is Δ T_f = i × K_f × m Hence, i= Δ T_fK_f × m Substitute values in the above expression. i ...

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Standard XII

Chemistry

Abnormal Colligative Properties

A complex is ...

Question

A complex is represented as $C o C l_{3} \cdot X N H_{3}$ . Its 0.1 molal solution in water shows $Δ T_{f} = {0.558}^{o} C$ . $K_{f}$ of $H_{2} O$ is 1.86 K/m. Assuming 100% ionisation, the number of $N H_{3}$ molecules associated with $C o$ is:

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Solution

The expression for the depression in the freezing point is $Δ T_{f} = i \times K_{f} \times m$
Hence, $i = \frac{Δ T_{f}}{K_{f} \times m}$
Substitute values in the above expression.
$i = \frac{0.558 K}{1.86 K / m \times 0.1 m} = 3$
Thus, the Van't Hoff factor is 3.
This indicates 1 molecule of the complex dissociates to give 3 ions.
Hence, the complex can be represented as $[C o (N H_{3})_{5} C l] C l_{2}$ .
$[C o (N H_{3})_{5} C l] C l_{2} ⇌ [C o (N H_{3})_{5} C l]^{2 +} + 2 C l^{-}$ .
Thus 5 ammonia molecules are associated with Co.

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A complex is represented as CoCl3⋅XNH3. Its 0.1 molal solution in water shows ΔTf=0.558oC. Kf of H2O is 1.86 K/m. Assuming 100% ionisation, the number of NH3 molecules associated with Co is:

A complex is represented as $C o C l_{3} \cdot X N H_{3}$ . Its 0.1 molal solution in water shows $Δ T_{f} = {0.558}^{o} C$ . $K_{f}$ of $H_{2} O$ is 1.86 K/m. Assuming 100% ionisation, the number of $N H_{3}$ molecules associated with $C o$ is: