AP EAMCET2010Chemistryd and f Block Elements
Which of the following is a correct statement?
Options
- AAqueous solutions of Cu ⁺ and Zn ²⁺ are colourless
- BAqueous solutions of Cu ²⁺ and Zn ²⁺ are colourless
- CAqueous solution of Fe ³⁺ is green in colour
- DAqueous solution of MnO ₄⁻ is colourless
Correct answer
A. Aqueous solutions of Cu ⁺ and Zn ²⁺ are colourless
Step-by-step solution
(a) Cu ⁺=[ Ar ] 3 d¹⁰ (No unpaired electrons, so it is colourless) Zn ²⁺=[ Ar ] 3 d¹⁰ (No unpaired electrons, so it is colourless) (b) Cu ²⁺=[ Ar ] 3 d^9 (One unpaired electron is present, so it is coloured) Zn ²⁺ is colourless. (c) The colour of Fe ²⁺ is green while that of Fe ³⁺ is blue. (d) MnO ₄⁻ contains no unpaired electrons, however, it is coloured due to charge transfer. Thus, only statement given in option (a) is correct.