Test 4 Extra Credit

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 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

a buffer solution is made of mixture of aqueous methanoic acid, HCOOH, with aqueous sodium methanoate, NaHCOO.

the equilibrium reaction takes place in buffer solution is :

HCOOH ↔ HCOO^- + H⁺

small amount of NaOH is then added to that buffer solution.

What reaction take places at the buffer solution to resist change of pH caused by addition of base?

• HCOOH + H⁺ → HCOOH₂

• HCOO^- + H⁺ → HCOOH

• HCOOH + OH^- → HCOO^- + H₂O

• HCOO^- + OH^- → COO^2- + H₂O

a buffer solution is made of mixture of aqueous ethanoic acid, CH₃COOH, with aqueous potassium ethanoate, KCH₃COO.

the equilibrium reaction takes place in buffer solution is :

CH₃COOH ↔ CH₃COO^- + H⁺

small amount of HCl is then added to that buffer solution.

What reaction take places at the buffer solution to resist change of pH caused by addition of acid?

• CH₃COO^- + H⁺ → CH₃COOH

• CH₃COO^- + OH^- → CH₂COO^2- + H₂O

• CH₃COOH + H⁺ → CH₃COOH₂

• CH₃COOH + OH^- → CH₃COO^- + H₂O

What is the concentration of citric acid if its volume is 25 ml and the titrated volume of the standard solution of 0.75 M is 12.4 ml

• 0.47

• 0.37

• 0.30

• 0.17

The concentration of OH– in a saturated solution of Mg(OH)₂ is 3.6 x 10^–4 M. The Ksp of Mg(OH)₂ is

• 1.3 x 10^–7

• 4.7 x 10^–11

• 3.6 x 10^–4

• 2.3 x 10^–11

The correct mathematical expression for finding the molar solubility (X) of Sn(OH)₂ is:

• 2(X)³ = Ksp

• 108(X)⁵ = Ksp

• 4(X)³ = Ksp

• 8(X)³ = Ksp

Barium carbonate has a measured solubility of 4.0 x 10^–5 at 25°C. Determine the Ksp.

• 5.3 x 10^–10

• 6.1 x 10^–5

• 9.1 x 10^–7

• 1.6 x 10^–9