EAMCET Engineering 2010 Solved Paper

(a) $\mathrm{Cu}^{+}=[\mathrm{Ar}]\,3d^{10}$(No unpaired electrons, so it is colourless)$\mathrm{Zn}^{2+}=[\mathrm{Ar}]\,3d^{10}$(No unpaired electrons, so it is colourless)(b) $\mathrm{Cu}^{2+}=[\mathrm{Ar}]\,3d^{9}$(One unpaired electron is present, so it is coloured)$\mathrm{Zn}^{2+}$ is colourless.(c) The colour of $\mathrm{Fe}^{2+}$ is green while that of $\mathrm{Fe}^{3+}$ is blue.(d) $\mathrm{MnO}_4^{-}$contains no unpaired electrons, however, it is coloured due to charge transfer.Thus, only statement given in option (a) is correct.