An aqueous solution of $\left[\mathrm{Mn}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}$ complex is pale pink in colour. The probable reasons for it are(A) Presence of $^{6}A_{1g}$ ground state(B) Disallowed transition by spin selection rule(C) Presence of $^{2}T_{2g}$ ground state(D) Charge transfer transitionThe correct answer is
(a)A and B
(b)A and C
(c)B and C
(d)C and D
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
High-spin Mn²⁺ (d⁵) has a ⁶A₁g ground state with no other sextet, so every d–d band is spin-forbidden and very weak. A and B (a).