In [Mn(H2O)6]2+, the Mn2+ ion has the electronic configuration [Ar]3d5. Due to this configuration, the d-d transitions are symmetry forbidden because the 3d5 configuration is stable and does not easily undergo transitions.
In [Ti(H2O)6]3+, the Ti3+ ion has the electronic configuration [Ar]3d1. The single electron in the 3d1 configuration can undergo d-d transitions, making them symmetry allowed.
Thus, the d-d transitions in [Mn(H2O)6]2+ are symmetry forbidden, while those in [Ti(H2O)6]3+ are symmetry allowed.
The correct answer is (B)
One mole of a monoatomic ideal gas starting from state A, goes through B and C to state D, as shown in the figure. Total change in entropy (in J K\(^{-1}\)) during this process is ............... 
The number of chiral carbon centers in the following molecule is ............... 
A tube fitted with a semipermeable membrane is dipped into 0.001 M NaCl solution at 300 K as shown in the figure. Assume density of the solvent and solution are the same. At equilibrium, the height of the liquid column \( h \) (in cm) is ......... 