Arrange the following in order of increasing acidic strength
(i) `HCOOH,ClCH_(2)COOH,CH_(3)COOH`
(ii) `CH_(3)COOH,(CH_(3))_(2)CHCOOH,(CH_(3))_(3)CCOOH`
(iii) `ClCH_(2)COOH,Cl_(2)CHCOOH,ClCl_(3)C.COOH`
(iv)`ClCH_(2)COOH,CH_(3)CH_(2)COOH,ClCH_(2)CH_(2)COOH,(CH_(3))_(2)CH.COOH,CH_(3)COOH.`

Explanation

To arrange the given carboxylic acids in order of increasing acidic strength, we need to consider the effects of electron-withdrawing groups (EWGs) and electron-donating groups (EDGs) on the acidity of the compounds. Electron-withdrawing groups increase acidity, while electron-donating groups decrease acidity.

### Step-by-Step Solution:

#### (i) HCOOH, ClCH₂COOH, CH₃COOH

1. **Identify the groups**:
- HCOOH (formic acid) has no substituents.
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