Question

Chloroacetic acid, HC₂H₂O₂Cl, is a stronger monoprotic acid than acetic acid. In a 0.10 M solution, the pH is 1.96.

Calculate the K_afor chloroacetic acid. Calculate the pK_a for chloroacetic acid.
Use the correct number of significant figures.

Answer 1

+ A [HA]=[HC,H,O,Cl]=0.10 Acid hydrolyis reaction is HA + H2O = H,0* Initial : 0.10 Change: -X Equilbrium : 0.10- x pH=1.96 [H,0* ]=10-196 =1.10x10-2 [A-]=1.10x10 [HA]=0.10- x =0.10-1.10x102 =0.0890 Acidity constant expression for the reaction: Ka_[H,0"][A 7 Ka [HA] (1.10x10-)(4.07 10-) Ka=' 0.0890 = 1.36x10-