【General guidance】The answer provided below has been developed in a clear step by step manner.Step1/1Sodium propinoate - A- at equivalence point-VHCl = 50 ml x 0.2 M / 0.1 M = 100 mlat 0%-A- + H2O -> HA + OH- 0.2 0 0-x +x +x0.2-x x xKb = x2 / (0.2-x) = 0.75 x 10-9 x = 0.122 x 10-4 MpOH = -log(0.122 x 10-4)pOH = 4.91pH = 14 - 4.91 = 9.09at 10% -Volume of HCl = 10 mlmoles of HCl = 10 ml x 0.1 M = 1 mmolmoles of A- = 50 ml x 0.2 M = 10 mmolA- + HCl -> HA10 1 0-1 -1 +19 0 1pH = pka + log([A^-]/[HA])pH = 4.874 + log(9/1)pH = 5.83at 50% - half equivalence pointpH = pka = 4.874at 90%-Volume of HCl = 90 mlmoles of HCl = 90 ... See the full answer