NEET 2022 Chemistry IUPAC Nomenclature MCQ Question

The correct name is:

$$\boxed{\text{diaquasilver(I) dicyanidoargentate(I)}}$$

In the original NEET 2022 Set S₁, this was Option (2); different paper codes rearranged the options. (MBBS Admission Abroad)

Chapter: Coordination Compounds

Class: 12 | Topic: IUPAC Nomenclature | Difficulty: 🟡 Moderate

✅ Correct Answer: B

Given:

$$[Ag(H_2O)_2][Ag(CN)_2]$$

1. Cation: $[Ag(H_2O)_2]^+$

• $H_2O$ is a neutral ligand → aqua
• Two $H_2O$ → diaqua
• Ag oxidation state = $+1$

$$\rightarrow \text{diaquasilver(I)}$$

2. Anion: $[Ag(CN)_2]^-$

• $CN^-$ → cyanido
• Two $CN^-$ → dicyanido
• Let Ag oxidation state be $x$:

$$x+2(-1)=-1$$ $$x=+1$$

Since it is an anionic complex, silver becomes argentate.

$$\rightarrow \text{dicyanidoargentate(I)}$$

Therefore:

$$\boxed{\text{diaquasilver(I) dicyanidoargentate(I)}}$$

❌ Why other options are wrong?

• A: dicyanidosilver(I) diaquaargentate(I) ❌ — Cation must be named first; the anion comes second.
• C/D: Ag(II) ❌ — Both Ag atoms are $+1$, not $+2$.
• B ✅ — Correct order and oxidation states.

📌 NCERT: In coordination compounds, the cation is named first, followed by the anion. For anionic complexes, the metal name ends in “-ate”.

🧠 NEET Trick: Cation first → silver; anion → argentate; both Ag = +1.