1.217-g sample of commercial KOH, contaminated by Noel with K2CO3, was dissolved in water and the resulting solution was diluted to 500.00 mL. A 50.0 mL aliquot of the solution was treated with 40.0 mL of 0.05304 M HCl and boiled to remove CO2. The excess acid consumed 4.74 mL of 0.04983 M NaOH using phenolphthalein indicator. An excess of neutral BaCl2 was added to another 50.00 mL aliquot to precipitate the carbonate as BaCO3. The solution was then titrated with 28.56 mL of the acid to a phenolphthalein endpoint.   The important reactions are:   KOH + HCl  H2O + KCl K2CO3 + 2 HCl  CO2 + H2O + 2 KCl

A 1.217-g sample of commercial KOH, contaminated by Noel with K₂CO₃, was dissolved in water and the resulting solution was diluted to 500.00 mL. A 50.0 mL aliquot of the solution was treated with 40.0 mL of 0.05304 M HCl and boiled to remove CO₂. The excess acid consumed 4.74 mL of 0.04983 M NaOH using phenolphthalein indicator. An excess of neutral BaCl₂ was added to another 50.00 mL aliquot to precipitate the carbonate as BaCO₃. The solution was then titrated with 28.56 mL of the acid to a phenolphthalein endpoint.

The important reactions are:

KOH + HCl  H₂O + KCl

K₂CO₃ + 2 HCl  CO₂ + H₂O + 2 KCl 

Calculate the following items in (a) – (f).

a) Calculate the combined amount (mmol) of KOH and K₂CO₃ in the first aliquot.

b) Calculate the amount (mmol) of KOH.

c) Calculate the amount (mmol) K₂CO₃.

d) Calculate the percentage KOH (MW = 56.11 g/mol).

e) Calculate the percentage K₂CO₃ (MW = 138.21 g/mol).

f) Calculate the percentage H₂O