Buffers

The buffer solution is able to maintain pH by some events, except . . .

• The addition of a little acid

• The addition of a little base

• Dilution

• Addition of water

• The addition of excess acid

The following solution mixture which is/are buffer . . .

• NaH₂PO₄ and Na₂HPO₄

• NH₃ and (NH₄)₂SO₄

• HCOOH and Ba(HCOO)₂

• H₃PO₄ and NaH₂PO₄

• NaOH and Ba(HCOO)₂

The following mixture of solutions that form a buffer solution is . . .

• 50 mL CH₃COOH 0.2 M and 50 mL NaOH 0.1 M

• 50 mL CH₃COOH 0.2 M and 100 mL NaOH 0.1 M

• 50 mL HCl 0.2 M and 100 mL NH₄OH 0.1 M

• 50 mL HCl 0.2 M and 50 mL NH₄OH 0.1 M

• 50 mL HCl 0.2 M and 100 mL NaOH 0.1 M

The pH solution that consist of CH₃COOH 0.01 M and CH₃COONa 0.01 M with Ka = 10^-5 is . . .

• 4

• 5

• 6

• 8

• 9

Acidic buffer is made up of

• weak acid and weak base
• weak acid and its conjugate salt
• weak acid and its conjugate base
• strong acid and its conjugate base

Which solution A and B of equal volume and concentration mixed together to form a buffer?

• Nitric acid and potassium hydroxide
• Nitric acid and potassium nitrate
• Propanoic acid and potassium hydroxide
• Propanoic acid and potassium propanoate

Which combination will form a buffer solution?

• 100ml of 0.1M HCI with 50ml of 0.1M NaOH
• 100ml of 0.1M CH₃COOH with 50ml of 0.1M NaOH
• 50ml of 0.1M HCI with 100ml of 0.1M NaOH
• 50ml of 0.1M CH₃COOH with 100ml of 0.1M NaOH

Which of the following could be added to a solution of ethanoic acid to prepare a buffer?

• NaOH
• HCI
• NaCI
• More ethanoic acid

Which of the following statements ARE TRUE about buffer solution?

(you may choose more than one answer)

• pH of buffer solution will never change despite addition of small amount of base or acid

• Buffer can be made by mixing weak acid and salt of its conjugate base or by mixing weak base with salt of its conjugate acid

• Buffer has acid and base components that can work specifically to resist pH change

• the closer the ratio of concentration weak acid/base to the concentration of salt of its conjugate base/acid, the less effective the buffer to resist pH change

What statements CAN BE TRUE about acidic buffer?

(you may choose more than one answer)

• It's made of a mixture of weak acid and salt of its conjugate base

• Concentration of H⁺ ions in acidic buffer is greater than concentration of OH^- ions which is present in the solution

• Dilution of buffer by adding small amount of water doesn't change the pH of buffer solution

• acidic buffer usually works effectively at pH range of above 7