Question

A buffer is prepared by adding 1.00 L of 1.0 M HCl to 750 mL of 1.5 M NaHCOO.

What is the pH of this buffer? Ka

= 1.7

Answer 1

Concepts and reason

The concept used to solve this problem is based on buffer solutions.

The pH of an acidic buffer solution is determined with the help of Henderson-Hasselbalch equation.

Fundamentals

Buffer solutions are those which resists change in its pH when a small amount of an acid or a base are added to it. The Henderson-Hasselbalch equation is shown as follows:

Here, is concentration of salt and concentration of weak acid.

The dissociation of the acid is shown as follows:

Now, convert volume into liters as follows:

Now, total volume is calculated as follows:

Substitute for and 1.00 L for .

Now calculate the concentration in terms of molarity as follows:

And,

Now, Henderson-Hasselbalch equation is as follows:

Substitute 3.77 for , 0.125 for and 1 for .

Ans:

The pH of the given buffer is 2.87.