The structure of aspartic acid is given below. (A) The p K a 1, p a 2, and p K a 3 of ( A ), respectively, are: 1.88,3.65, and 9.60.p a 1 corresponds to the ionisation of the COOH group, of pK 2 corresponds to the ionisation of ( NH 3) (ammonium ion). What is the pH at isoelectric points (pI)?

Question

The structure of aspartic acid is given below.

(A) The p K a 1, p a 2, and p K a 3 of ( A ), respectively, are: 1.88,3.65, and 9.60.p a 1 corresponds to the ionisation of the COOH group, of

pK 2 corresponds to the ionisation of ( NH 3) (ammonium ion). What is the pH at isoelectric points (pI)? (A) ( p K a 1+ p K a 2/2) (B) ( p K a 1+ p K a 3/2) (C) ( p K a 2+ p K a 3/2) (D) ( p K a 1+ p K a 2+ p K a 3/3)

Tardigrade Admin · Accepted Answer

Correct answer is (a) ( p K a 1+ p K a 2/2)

$\frac{p K _{a_{1}} + p K _{a_{2}}}{2}$

$\frac{p K _{a_{1}} + p K _{a_{3}}}{2}$

$\frac{p K _{a_{2}} + p K _{a_{3}}}{2}$

$\frac{p K _{a_{1}} + p K _{a_{2}} + p K _{a_{3}}}{3}$

Correct answer is (a) $\frac{p K _{a_{1}} + p K _{a_{2}}}{2}$

2pKa1​​+pKa2​​​

2pKa1​​+pKa3​​​

2pKa2​​+pKa3​​​

3pKa1​​+pKa2​​+pKa3​​​

Correct answer is (a) 2pKa1​​+pKa2​​​

$\frac{p K _{a_{1}} + p K _{a_{2}}}{2}$

$\frac{p K _{a_{1}} + p K _{a_{3}}}{2}$

$\frac{p K _{a_{2}} + p K _{a_{3}}}{2}$

$\frac{p K _{a_{1}} + p K _{a_{2}} + p K _{a_{3}}}{3}$

Correct answer is (a) $\frac{p K _{a_{1}} + p K _{a_{2}}}{2}$