Question

A novel triprotic acid (3 carboxylic acids) has pKa1 = 3.0, pKa2 = 5.0, and pKa3 = 6.50. At pH = 4.0, what is the APPROXIMATE percentage of Acid(2H)- (loss of 1 proton) versus total amount of Acid in solution?

	a.	50%
	b.	80%
	c.	0%
	d.	25%
	e.	90%

Answer 1

Ang A Toriprotic acid like hod, when o clealds to HoatHt. qt will form buffer solution. Here H₂A in salt .. Hence, for buffer solution, we have equation, a [salt] - pH = pkat log Treid plaag.o. pH=4.0. Hence, 4.0=3.0 + tog is all -) log Thy A T. 1.0 1.0 ? TH3 A] - 2A2A -10 Italy A3 Henee, [H2H] : 10 TH3 A] : Converting to percentage it is 90.9% correct answer is 90.9%