In an electric field, if an amino acid migrates towards cathode, the pH of the solution is said to be

Options

A. less than pI
B. more than pI
C. equal than pI
D. 7 (seven)

Explanation

To solve the question, we need to understand the behavior of amino acids in an electric field and the concept of isoelectric point (pI). Here’s the step-by-step solution:

### Step 1: Understand Amino Acid Behavior in an Electric Field
Amino acids can exist in different forms depending on the pH of the solution. At a certain pH, they exist as zwitterions, which means they have both positive and negative charges but are overall neutral.

**Hint:** Recall that zwitterions are the form of amino acids that have both a positive and a negative charge.

### Step 2: Identify the Direction of Migration
In an electric field, positively charged ions migrate towards the cathode (negative electrode). Therefore, if an amino acid is migrating towards the cathode, it must be in a positively charged form.

**Hint:** Remember that positively charged species move towards the negative electrode (cathode).

### Step 3: Determine the pH Condition
For an amino acid to have a positive charge, the pH of the solution must be below its isoelectric point (pI). At pI, the amino acid exists as a zwitterion and does not migrate towards either electrode.

**Hint:** The isoelectric point (pI) is the pH at which the amino acid has no net charge.

### Step 4: Conclusion
Since the amino acid is migrating towards the cathode, we conclude that the pH of the solution is less than the isoelectric point (pI).

**Final Answer:** The pH of the solution is less than pI.

### Summary of Steps:
1. Understand that amino acids can exist as zwitterions.
2. Recognize that positively charged ions move towards the cathode.
3. Identify that a positive charge indicates the pH is below the isoelectric point.
4. Conclude that the pH of the solution is less than pI.