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 step by step.

### Step 1: Analyze the structure of glycine
Glycine is the simplest amino acid with the following structure:
- It has an amino group (-NH2)
- A carboxylic acid group (-COOH)
- A hydrogen atom and a side chain (which is just another hydrogen atom in the case of glycine).

### Step 2: Evaluate the statements
1. **Statement 1: It exists in crystalline form.**
- Glycine is known to form crystals due to its ionic nature. Therefore, this statement is **true**.

2. **Statement 2: It is optically active.**
- For a compound to be optically active, it must have a chiral center, meaning it must have four different substituents attached to a carbon atom. In glycine, the central carbon is attached to two hydrogen atoms, making it achiral. Therefore, this statement is **false**.

3. **Statement 3: It is soluble in water.**
- Glycine is ionic in nature due to the presence of both amino and carboxylic groups, which allows it to interact with water molecules. Thus, this statement is **true**.

4. **Statement 4: It can form zwitter ions.**
- Glycine can exist as a zwitterion, where it has both a positive and a negative charge within the same molecule. This occurs when the amino group accepts a proton and the carboxylic group donates a proton. Therefore, this statement is **true**.

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

Thus, the true statements about glycine are 1, 3, and 4.

### Final Answer
The correct statements about glycine are **1, 3, and 4**.

---