Match the column.
`{:("Column-I","Column-I"),("(a) Schimdt reaction",(p) RCOOH underset(Delta)overset(NaOH//CaO)toRH),("(b) Curtius reaction",(q)R-CH_(2)COOH underset(Delta)overset("Red "P//X_(2))toR-underset(X)underset(|)CH-COOH),("(c) Decarboxylation",(r) RCOCl underset({:(" "Delta),((ii)H_(3)O):})overset((i)NaN_(3))to RNH_(2)),("(d) HVZ reaction",(s)RCOOH underset(Delta)overset(N_(3)H)toRNH_(2)):}`

Answer

To solve the matching question, we will analyze each reaction in Column I and match it with the appropriate reaction in Column II.

### Step-by-Step Solution:

1. **Identify the Schimdt Reaction**:
- The Schmidt reaction involves the reaction of a carboxylic acid with azide, which leads to the formation of an amine.
- In this case, the reaction can be represented as:
\[ \text{RCOOH} + \text{NaN}_3 \xrightarrow{\Delta} \text{RH} + \text{N}_2 \]
- **Match**: (a) Schmidt reaction → (s) RCOOH under Δ over NaOH/CaO to RH.

2. **Identify the Curtius Reaction**:
- The Curtius reaction involves the conversion of an acyl azide to an isocyanate, which upon hydrolysis yields an amine.
- The reaction can be represented as:
\[ \text{RCOCl} + \text{NaN}_3 \xrightarrow{\Delta} \text{R-N=C=O} \xrightarrow{\text{H}_2\text{O}} \text{RNH}_2 \]
- **Match**: (b) Curtius reaction → (r) R-CH₂COOH under Δ over "Red P/X₂" to R-CH-COOH.

3. **Identify Decarboxylation**:
- Decarboxylation is the process of removing a carboxyl group (CO₂) from a carboxylic acid, typically by heating.
- The reaction can be represented as:
\[ \text{RCOOH} \xrightarrow{\Delta} \text{RH} + \text{CO}_2 \]
- **Match**: (c) Decarboxylation → (p) RCOOH under Δ over NaOH/CaO to RH.

4. **Identify the HVZ Reaction**:
- The HVZ (Hale-Wolhard-Zelinski) reaction involves the halogenation of a carboxylic acid at the alpha position in the presence of red phosphorus.
- The reaction can be represented as:
\[ \text{RCH}_2\text{COOH} \xrightarrow{\text{Red P}} \text{RCHXCOOH} \]
- **Match**: (d) HVZ reaction → (q) RCOOH under Δ over N₃H to RNH₂.

### Final Matches:
- (a) Schmidt reaction → (s)
- (b) Curtius reaction → (r)
- (c) Decarboxylation → (p)
- (d) HVZ reaction → (q)

### Summary of Matches:
- A → S
- B → R
- C → P
- D → Q