Consider the following statements with respect to the base hydrolysis of $\left[\mathrm{CoCl}\left(\mathrm{NH}_{3}\right)_{5}\right]$ to $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5}(\mathrm{OH})\right]^{2+}$A. One of the ammonia ligands acts as a Bronsted acid.B. The entering group is water.C. A heptacoordinated $\mathrm{Co}^{3+}$ species is an intermediate.The correct statement(s) is/are
(a)A and B
(b)A and C
(c)B and C
(d)C only
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
In S_N1CB one NH₃ ligand is deprotonated (acts as a Brønsted acid) and the five-coordinate amido intermediate then takes up water, which loses a proton to give the hydroxo product; no seven-coordinate species is involved. A and B.