Consider that a d⁶ metal ion (M²⁺) forms a complex with aqua ligands, and the spin only magnetic moment of the complex is 4.90 BM. The geometry and the crystal field stabilization energy of the complex is

For the following Assertion and Reason, the correct option is

Assertion (A): When Cu (II) and sulphide ions are mixed, they react together extremely quickly to give a solid.

Reason (R): The equilibrium constant of
Cu²⁺(aq) + S^2–(aq) ⇌ CuS(s) is high because the solubility product is low.

The Gibbs change (in J) for the given reaction at
[Cu²⁺] = [Sn²⁺] = 1 M and 298K is :

Cu(s) + Sn²⁺(aq.) $$ \to $$ Cu²⁺(aq.) + Sn(s);

($$E_{S{n^{2 + }}|Sn}^0 = - 0.16\,V$$,
$$E_{C{u^{2 + }}|Cu}^0 = 0.34\,V$$)
Take F = 96500 C mol^–1)

Which of the following compunds will show retention in configuration on nucleophilic substitution by OH^– ion?