Which of the following is optically active?

Options

A. Ethylene glycol
B. Oxalic acid
C. Glycerol
D. Tartaric acid

Answer

To determine which of the given compounds is optically active, we need to identify if they contain any chiral centers. A chiral center is typically a carbon atom that is bonded to four different groups. Let's analyze each option step-by-step.

### Step 1: Analyze Ethylene Glycol
- **Structure**: Ethylene glycol has the formula \( \text{HO-CH}_2-\text{CH}_2-\text{OH} \).
- **Chirality Check**:
- The first carbon is attached to two hydrogen atoms and one hydroxyl group (OH) and one carbon atom.
- The second carbon is similarly attached to two hydrogen atoms and one hydroxyl group and one carbon atom.
- **Conclusion**: Both carbons are not chiral because they are not attached to four different groups.
- **Result**: Ethylene glycol is **not optically active**.

### Step 2: Analyze Oxalic Acid
- **Structure**: Oxalic acid has the formula \( \text{HOOC-COOH} \).
- **Chirality Check**:
- The carbon atoms are each bonded to two oxygen atoms (due to the double bonds) and one hydroxyl group.
- **Conclusion**: Neither carbon is chiral as they do not have four different substituents.
- **Result**: Oxalic acid is **not optically active**.

### Step 3: Analyze Glycerol
- **Structure**: Glycerol has the formula \( \text{HO-CH}_2-\text{CHOH}-\text{CH}_2-\text{OH} \).
- **Chirality Check**:
- The first carbon is attached to two hydrogen atoms and one hydroxyl group.
- The second carbon is attached to one hydroxyl group and two hydrogen atoms.
- The third carbon is also attached to two hydrogen atoms and one hydroxyl group.
- **Conclusion**: None of the carbons are chiral as they do not have four different groups.
- **Result**: Glycerol is **not optically active**.

### Step 4: Analyze Tartaric Acid
- **Structure**: Tartaric acid has the formula \( \text{HOOC-CHOH-CHOH-COOH} \).
- **Chirality Check**:
- The first carbon (attached to COOH) is bonded to four different groups: COOH, OH, H, and the rest of the molecule.
- The second carbon (attached to OH) is also bonded to four different groups: COOH, OH, H, and the rest of the molecule.
- **Conclusion**: Both of these carbons are chiral.
- **Result**: Tartaric acid is **optically active**.

### Final Answer
The compound that is optically active is **Tartaric Acid**.

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