The correct order of acidic strength of the following is
(I) Oxalic acid `HOOC-COOH`
(II) Malonic acid
`HOOC-CH_(2)-COOH`
(III) Succinic acid
`HOOC-(CH_(2))_(2)-COOH`
(IV) Glutaric acid
`HOOC-(CH_(2))_(3)-COOH`

Options

A. I gt II gt III gt IV
B. I gt III gt II gt IV
C. IV gt III gt II gt I
D. IV gt II gt III gt I

Answer

To determine the correct order of acidic strength for the given acids (oxalic acid, malonic acid, succinic acid, and glutaric acid), we will analyze the structure and the effect of alkyl groups on acidity.

### Step-by-Step Solution:

1. **Identify the Structures of the Acids:**
- Oxalic acid: `HOOC-COOH`
- Malonic acid: `HOOC-CH₂-COOH`
- Succinic acid: `HOOC-(CH₂)₂-COOH`
- Glutaric acid: `HOOC-(CH₂)₃-COOH`

2. **Understand the Effect of Alkyl Groups on Acidity:**
- The presence of alkyl groups in carboxylic acids can affect the stability of the conjugate base formed after deprotonation. More alkyl groups generally lead to decreased acidity because they destabilize the negative charge on the conjugate base due to their electron-donating effect.

3. **Count the Alkyl Groups:**
- Oxalic acid has **0 alkyl groups**.
- Malonic acid has **1 alkyl group**.
- Succinic acid has **2 alkyl groups**.
- Glutaric acid has **3 alkyl groups**.

4. **Determine the Order of Acidity:**
- Since oxalic acid has the least number of alkyl groups, it will be the most acidic.
- Malonic acid, with one alkyl group, will be less acidic than oxalic acid but more acidic than succinic acid.
- Succinic acid, with two alkyl groups, will be less acidic than malonic acid.
- Glutaric acid, with three alkyl groups, will be the least acidic.

5. **Final Order of Acidity:**
- Therefore, the correct order of acidic strength is:
\[ \text{Oxalic acid} > \text{Malonic acid} > \text{Succinic acid} > \text{Glutaric acid} \]
- In symbolic form: \( \text{I} > \text{II} > \text{III} > \text{IV} \)