Question

In: Chemistry

You are given 60 mL of 0.50 M acetic acid/acetate buffer to test. The starting composition of the two major species are:

Concentration of CH3COOH: 0.300 M

Concentration of CH3COO-: 0.200 M

a) You add 1.0 mL of 1.00 M HCl to the buffer. Calculate the molarity of H3O+ added as HCl, and the final molarities of acetic acid and acetate ion at equilibrium. What is the new value of the pH?

b) Now take a fresh 60 mL of the buffer and add 1.0 mL of 1.00 M NaOH. Using steps similar to those above, calculate the new pH of the solution.

Expert Solution

a) You add 1.0 mL of 1.00 M HCl to the buffer.

The molarity of added as HCl

The added ions will react with sodium acetate to form acetic acid. Hence, the molarity of acetic acid will increase and the molarity of sodium acetate will decrease.

The final molarity of acetic acid at equilibrium

The final molarity of acetate ion at equilibrium

The pH of the solution is

(b) You add 1.0 mL of 1.00 M NaOH to the buffer.

The molarity of added as NaOH

The added ions will react with acetic acid to form sodium acetate . Hence, the molarity of acetic acid will decrease and the molarity of sodium acetate will increase.

The final molarity of acetic acid at equilibrium

The final molarity of acetate ion at equilibrium

The pH of the solution is

queen_honey_blossom answered 2 years ago

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