Answer to Question #212414 in General Chemistry for xiu

Question

Acetylsalicylic acid, HA is an active ingredient in aspirin, has Ka value of 3.0 x10-5 . In order to determine its chemical reactivity, 0.1 mole acetylsalicylic acid is dissolve in 1L of water.

a) Calculate the concentrations of all species in the acetylsalicylic acid solution [6 marks] b) Determine the pH of solution [1 mark]

c) If 100 mL of acetylsalicylic acid sample is titrated with 100 mL of 0.1 M NaOH, what is the pH of this mixture at equivalence point? 

Answer 1

C₉H₈O₄ + NaOH → C₉H₇O₄Na + H₂O

Mole ratio = 1:1

PH = -log {H⁺}

PH = - log{0.1}=1