Question

What is the buffer capacity for a solution that requires 3.35 mL of 0.10 M HCl to change the pH by 1 unit?

Answer 1

For solving this question we require the volume of solution whose pH increases by 1 on addition of 3.35 mL of 0.10 M HCl.

I am assuming it to b "V" here. You can substitute the value of V to get your result.

Buffer capacity is calculated as the amount(in gm-eq) of strong acid or base that must be added to 1 L of buffer solution to change its pH by 1 unit.

In the question we are provided with the amount of HCl required to raise the pH of V ml of solution. By simple stochiometry we can calculate the amount for 1 L of solution.

Moles of HCl = Molarity of HCl Volume of HCl added = .00335 L 0.10 moles/L = 0.000335 moles

Since HCl is monobasic acid, its n factor is 1 and Number of gm-eq = number of moles/1.

So, we require 0.000335 gm-eq of HCl per V ml of buffer solution. For 1L (1000 ml) of buffer solution we will require:

gm-eq of HCl.

Buffer capacity =