Which among the following statements are true for glycine?
1. It exists in crsytalline form
2. It is optically active
3. It is soluble in water
4. It can form Zwitter ions

Options

A. 1, 2 and 3
B. 1, 2 and 4
C. 1, 3 and 4
D. 2, 3 and 4

Answer

To determine which statements about glycine are true, we will analyze each statement one by one.

### Step 1: Analyze Statement 1 - "It exists in crystalline form."
Glycine is an amino acid that can crystallize. It forms well-defined crystals under appropriate conditions. Therefore, this statement is **true**.

### Step 2: Analyze Statement 2 - "It is optically active."
Optical activity refers to the ability of a compound to rotate plane-polarized light, which typically occurs in chiral molecules. Glycine is the simplest amino acid and does not have a chiral center (it has two hydrogen atoms attached to the alpha carbon). Therefore, glycine is **not optically active**, making this statement **false**.

### Step 3: Analyze Statement 3 - "It is soluble in water."
Glycine is a polar molecule due to the presence of both an amino group (-NH2) and a carboxylic group (-COOH). These functional groups can form hydrogen bonds with water, which makes glycine soluble in water. Thus, this statement is **true**.

### Step 4: Analyze Statement 4 - "It can form Zwitter ions."
A zwitterion is a molecule that has both positive and negative charges but is overall electrically neutral. Glycine can exist as a zwitterion in solution, where the amino group is protonated (NH3+) and the carboxylic group is deprotonated (COO-). Therefore, this statement is **true**.

### Conclusion:
Based on the analysis:
- Statement 1: True
- Statement 2: False
- Statement 3: True
- Statement 4: True

The true statements about glycine are 1, 3, and 4.

### Final Answer:
The correct options are A (It exists in crystalline form), C (It is soluble in water), and D (It can form Zwitter ions).

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