1. A sample of potassium hydrogen phthalate (KHCgH404), which is an acid, with a
ID: 592253 • Letter: 1
Question
1. A sample of potassium hydrogen phthalate (KHCgH404), which is an acid, with a mass of 0.3650 g is dissolved in water and used to standardize a solution of potassium hydroxide. An endpoint is reached when 20.63 mL of potassium hydroxide has been added. Determine the molarity (in mol/L) of the potassium hydroxide solution. Report your answer to four significant figures. Tries 0/3 2. The standardized potassium hydroxide solution is then used to titrate 15.43 mL of a solution of chlorcacetic acid (CIH2CCOOH). An endpoint is reached when 37.63 mL of potassium hydroxide has been added Determine the molarity (in mol/L) of the chloroacetic acid solution. Report your answer to four significant figures.Explanation / Answer
1)
HC8H4O4- (aq) + OH- (aq)-------> C8H4O4-2 ( aq) + H2O (l)
moles of HC8H4O4- = 0.3650 / 204.22
= 1.787 x 10^-3 mol
moles of KOH = moles of KHP
moles of KOH = 1.787 x 10^-3 mol
0.02063 x M = 1.787 x 10^-3
M = 0.0866
Molarity of KOH = 0.08662 M
2)
ClH2CCOOH + KOH --------------> ClHCCOOH- + H2O
moles of KOH = moles of ClH2CCOOH
mmoles of KOH = 37.63 x 0.0866 = 3.26
moles of ClH2CCOOH = 3.26
15.43 x M = 3.26
M = 0.211
Molarity of KOH = 0.2113 M
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