(a) Which of the following species cannot act as a ligand ? Give reason. $\text{OH}^-$, $\text{NH}_4^+$, $\text{CH}_3\text{NH}_2$, $\text{H}_2\text{O}$ (b) The complex $[\text{Co}(\text{NH}_3)_5(\text{NO}_2)]\text{Cl}_2$ is red in colour. Give IUPAC name of its linkage isomer.

Year	Paper Code	Set	Position
CBSE 2023	Series Other	Set 1	Question 21
CBSE 2023	Series Other	Set 1	Question 19
CBSE 2023	Series Other	Set 1	Question 20

• Step 1: Stating the fundamental formula / law statement (+1 Mark)
• Step 2: Intermediate mathematical substitution or proof steps (+1 Mark)
• Step 3: Correct final value or conclusion with mandatory SI units (+1 Mark)