Statement I: At isoelectric point of alanine (pI = 6.01), it moves towards cathode

Statement II: At isoelectric point the solution of amino acid is neutral

Statement I is false but Statement II is correct

The correct answer is option 4. Statement I is false but Statement II is correct.

To determine the correct answer, let us analyze each statement:

Statement I: At isoelectric point of alanine (pI = 6.01), it moves towards the cathode

Isoelectric Point (pI): The isoelectric point is the pH at which an amino acid has no net electrical charge. For alanine, this is pH 6.01.

Behavior at pI: At the isoelectric point, an amino acid exists primarily in its zwitterionic form, where the overall charge is zero (neutral). Therefore, it does not migrate towards either electrode in an electric field because there is no net charge to drive the movement.

Statement II: At isoelectric point the solution of amino acid is neutral

Neutrality at pI: At the isoelectric point, the amino acid molecule has an equal number of positive and negative charges, resulting in no net charge. Thus, the solution is neutral in terms of the net charge of the amino acid molecules.

Given these points:

Statement I is false because at the isoelectric point, alanine does not move towards the cathode or anode. It remains stationary in an electric field due to its net neutral charge. Statement II is correct because at the isoelectric point, the amino acid is neutral with no net charge.

Therefore, the correct answer is: Statement I is false but Statement II is correct.

Here is the detailed reasoning:

Detailed Explanation:

Isoelectric Point (pI): For alanine, the pI is 6.01. At this pH, alanine exists predominantly in its zwitterionic form \((NH_3^+–CH(CH_3)–COO^-)\), where the positive and negative charges balance each other out, making the overall charge zero.

Behavior in Electric Field: If the pH of the solution is above the pI, alanine will carry a net negative charge and move towards the anode (positive electrode). If the pH of the solution is below the pI, alanine will carry a net positive charge and move towards the cathode (negative electrode). At the pI (6.01 for alanine), the amino acid has no net charge and does not move in an electric field.

Neutral Solution at pI: The concept of neutrality at the pI refers to the balance of charges on the amino acid molecule itself, not the pH of the solution. The amino acid is in a form where its net charge is zero, hence considered "neutral" in terms of charge.

Given this explanation, Statement I is incorrect while Statement II is correct. Thus, the correct conclusion is that: Statement I is false but Statement II is correct.