Question

A sample of impure KHP is found to contain 27.65% KHP. How many milliliters of a 0.1159 M NaOH solution would be required to titrate a solution containing 2.4791 g of the impure KPH sample dissolved in 25.00 mL of water. The molar mass of KPH is 204.219 g/mol.

Answer 1

Balanced reaction is

KHP + NaOH NaKP + H₂O

Mole ratio of KHP and NaOH = 1:1.

Pure Mass KHP = impure mass ×

= 2.4791×

= 0.685 g.

Moles of KHP = ( Mass / molar mass)

= ( 0.685/204.219)

= 0.0034

Now , moles of NaOH = 0.0034

Or, molarity × volume = moles of NaOH

Or, 0.1159× volume = 0.0034

Or, Volume = (0.0034/0.1159) = 0.02896 L = 28.96 mL.

Therefore volume of NaOH solution needed to titrate

= 28.96 mL.