How do the following react when heated and when treated with concentrated `H_2 SO_4` :
(i) `HCOOH` and (ii) `(COOH)_2` ?

Explanation

To solve the question regarding the reactions of formic acid (HCOOH) and oxalic acid ((COOH)₂) when heated and treated with concentrated sulfuric acid (H₂SO₄), we will analyze each compound step by step.

### Step 1: Reaction of Formic Acid (HCOOH)

**When heated:**
1. Formic acid can decompose upon heating.
2. The decomposition leads to the formation of carbon monoxide (CO) and water (H₂O).
3. The reaction can be summarized as:
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