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TS EAMCET · Chemistry · d and f Block Elements

Which of the following molecules is colourless?

  1. A \(\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}\) (crystal)
  2. B \(\mathrm{CuSO}_4\) (anhydrous)
  3. C \(\left[\mathrm{Cu}\left(\mathrm{NH}_3\right)_4\right]^{2+}(\mathrm{aq})\)
  4. D \(\left[\mathrm{CuCl}_4\right]^{2-}(\mathrm{aq})\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\mathrm{CuSO}_4\) (anhydrous)

Step-by-step Solution

Detailed explanation

Hydrated copper sulphate \(\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}\) is blue in colour. The ligand (water) molecules causes splitting of \(d\)-orbitals. This facilitated \(d\) - \(d\) transition and colour. Anhydrous copper sulphate \(\mathrm{CuSO}_4\) is colourless. In…