Question

Which of the following cannot show linkage isomerism?

• A. NO$_2^-$
• B. SCN$^-$
• C. CN$^-$
• D. NH$_3$

Hint:

Linkage isomerism occurs in ligands that can coordinate through more than one atom, such as NO$_2^-$, SCN$^-$, and CN$^-$, but not NH$_3$.

Answer 1

The Correct Option is D

Step 1: Define linkage isomerism.
Linkage isomerism occurs when a ligand can bind to the metal center in more than one way. This typically happens with ligands that have more than one donor atom, such as NO$_2^-$, SCN$^-$, and CN$^-$.
Step 2: Analyze the options.
- NO$_2^-$ can bind through the nitrogen atom or the oxygen atom, so it can exhibit linkage isomerism. - SCN$^-$ can bind through either the sulfur or nitrogen atom, so it can also show linkage isomerism. - CN$^-$ can bind through the carbon atom or the nitrogen atom, so it can show linkage isomerism. - NH$_3$, however, only binds through the nitrogen atom and does not show linkage isomerism.
Step 3: Apply to the options.
Since NH$_3$ cannot show linkage isomerism, the correct answer is (D).
Final Answer: \[ \boxed{\text{NH}_3} \]