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Your job is to determine the concentration of ammonia in a commercial window cle

ID: 522847 • Letter: Y

Question

Your job is to determine the concentration of ammonia in a commercial window cleaner. In the titration of a 25.00 mL sample of the cleaner, the equivalence point is reached after 16.85 mL of 0.138 M HCl has been added. What is the initial concentration of ammonia in the solution? What is the pH of the solution at the equivalence point? 0.0555 M ammonia 9.26 pH The volume of the original cleaner is only 25.00 mL. The diluted volume of the titrated solution does not change the volume of the cleaner itself.

Explanation / Answer

C1 V1 = C2 V2

C1 x 25 = 0.138 x 16.85

C1 = 0.0930 M

molarity of NH3 = 0.0930 M

pH = 14- 1/2 [pKb -logC]

pH = 14 - 1/2 [4.74 - log 0.0930]

pH   = 11.11