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QJEEAdv15Ch949f: JEE Advanced 2015 Chemistry - Class 12 JEEAdv15Ch949f Solution: If the freezing point of a 0.01 molal aqueous solution of a…

If the freezing point of a 0.01 molal aqueous solution of a cobalt (III) chloride-ammonia complex(which behaves as a strong electrolyte) is – 0.0558oC, the number of chloride(s) in the coordination sphere of the complex is [Kf of water = 1.86 K kg mol–1 ]

Step-by-Step Verified Solution

The depression in freezing point is given by

ΔTf = Kf × m × i

0.0558 = 1.86 × 0.01 × i

i = 3

Therefore, one mole of complex gives three moles of ions in solution.

Hence, the complex is [Co(NH3)5Cl]Cl2 and the number of Cl− ions inside the coordination sphere is 1.

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