1.An aqueous solution contains 0.305 M ammonia. Calculate the pH of the solution

Question

1.An aqueous solution contains 0.305 M ammonia. Calculate the pH of the solution after the addition of 1.58×10-2 moles of perchloric acid to 125 mL of this solution. (Assume that the volume does not change upon adding perchloric acid.) pH =

An aqueous solution contains 0.465 M hypochlorous acid.

2.Calculate the pH of the solution after the addition of 3.53×10-2 moles of potassium hydroxide to 155 mL of this solution.
(Assume that the volume does not change upon adding potassium hydroxide)pH =

3.When a 29.6 mL sample of a 0.327 M aqueous hydrofluoric acid solution is titrated with a 0.370 M aqueous sodium hydroxidesolution, what is the pH after 39.2 mL of sodium hydroxide have been added?
pH =

4.A 48.0 mL sample of a 0.406 M aqueous hypochlorous acid solution is titrated with a 0.342 M aqueous sodium hydroxide solution. What is the pH after 19.1 mL of base have been added?pH =

Explanation / Answer

(1)

The expression for pOh for buffer is,

pOH = pKb + log(NH4/NH3)

Moles of ammonia =( 0.305 mole/L )x (0.125 L ) = 0.038125 moles

mmol of acid = 1.58×10-2 moles

NH3 = 0.038125 moles - 1.58×10-2 moles = 0.022325 moles

NH4+ = 1.58×10-2 moles formed

then

pOH = 4.75 + log(1.58×10-2 moles/ 0.022325 moles) = 4.60

pH = 14-4.60 =9.40

pH=9.40

Post questions separately

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.