Question

Which of the following compounds is not coloured?

विकल्प

• Na₂[CuCl₄]

• Na₃[AlF₆]

• K₄[Fe(CN)₆]

• K₃[Fe(CN)₆]

Answer 1

Na₃[AlF₆]

Explanation:

• Na₂[CuCl₄]: Contains Cu²⁺, which has unpaired d-electrons, making the compound coloured.
• K₃[Fe(CN)₆]: Contains Fe²⁺, which has unpaired d-electrons, giving it colour.
• K₄[Fe(CN)₆]: Contains Fe³⁺, which also has unpaired d-electrons, making it coloured.
• Na₃[AlF₆]: Contains Al³⁺, which has no d-electrons, and F⁻ is a weak ligand, so the compound is colourless.

Thus, Na₃[AlF₆] is not coloured.