PH Calculations

Determine the pH of a 0.35 M aqueous solution of CH3NH2 (methylamine). The Kb of methylamine is 4.4 x 10^-4.

• 10.00

• 3.86

• 12.09

• 1.96

HZ is a weak acid. An aqueous solution of HZ is prepared by dissolving 0.020 mol of HZ in sufficient water to yield 1.0 L of solution. The pH of the solution was 4.93 at 25.0°C. The Ka of HZ is __________.

• 1.2 x 10^-5

• 6.9 x 10^-9

• 1.4 x 10^-10

• 9.9 x 10-²

The Ka for HCN is 4.9 x 10^-10. What is the value of Kb for CN-?

• 2.0 x 10^-5

• 4.0 x 10^-6

• 4.9 x 10^-24

• 2.0 x 10⁹

Calculate the pH of 0.726 M anilinium hydrochloride (C6H5NH3Cl) solution in water, given that Kb for aniline is 3.83 x 10^-4.

• 1.77

• 12.64

• 5.36

• 8.64

Kb for NH3 is 1.8 x 10^-5. What is the pH of a 0.35 M aqueous solution of NH4Cl at 25.0°C?

• 9.76

• 4.35

• 9.11

• 4.86

The Ka for formic acid (HCO2H) is 1.8 x 10^-4. What is the pH of a 0.35 M aqueous solution of sodium formate (NaHCO2)?

• 11.64

• 5.42

• 4.26

• 8.64

Ka for HCN is 4.9 x 10^-10. What is the pH of a 0.068 M aqueous solution of sodium cyanide?

• 2.96

• 11.07

• 13.24

• 7.00

The pH of a 0.15 M aqueous solution of NaZ (the sodium salt of HZ) is 10.7. What is the Ka for HZ?

• 1.6 x 10^-6

• 6.0 x 10^-9

• 8.9 x 10^-4

• 1.3 x 10^-12

A 1.0 x 10^-4 M solution of HNO₃ has a [H⁺] concentration of: (Notice HNO₃ has one H⁺.)

• 1.0 x 10^-14

• log 1.0 x 10^-4

• 1.0 x 10^-10

• 1.0 x 10^-4

A solution of KOH is 2.5 x 10^-5 M. What is the [H⁺] concentration? (Hint: Find pOH, then pH, then [H⁺].)

• 4.60

• 9.40

• 3.98 x 10^-10

• 1.0 x 10^-4.60