www-awh.aleks.com 2 My Academics ALEKS Homework... Christian James Ansley Davis
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www-awh.aleks.com 2 My Academics ALEKS Homework... Christian James Ansley Davis Lea.. nach3co2 molar m...Chegg Study | Gui.... l Safari File Edit Vi... Chemistry questio...+ O ACIDS AND BASES Calculating the pH of a weak acid titrated with a strong b Ansley An analytical chemist is titrating 196.7 mL of a 0.3700 M solution of cyanic acid (HCNO) with a 0.5100 M solution of KOH. The pK of cyanic acid is 3.46. Calculate the pH of the acid solution after the chemist has added 170.6 mL of the KOH solution to it Note for advanced students: you may assume the final volume equals the initial volume of the solution plus the volume of KOH solution added. Round your answer to 2 decimal places. Ar pH = Explanation CheckExplanation / Answer
no of moles of HCNO = molarity * volume in L
= 0.37*0.1967 = 0.072779 moles
no of moles of KOH = molarity * volume in L
= 0.51*0.1706 = 0.087006 moles
no of moles of excess of KOH = 0.087006 - 0.072779 = 0.014227moles
Total volume of solution = 196.7+170.6 = 367.3ml = 0.3673L
molarity of KOH = no of moles/volume in L
= 0.014227/0.3673 = 0.03873M
KOH(aq) -----------> K^+ (aq) + OH^- (aq)
0.03873M 0.03873M
[OH^-] = [KOH]
[OH^-] = 0.03873
POH = -log[OH^-]
= -log0.03873
= 1.412
PH = 14-POH
=14-1.412 = 12.58
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