Question

a 5ml saturated sample of borax was collected at 49.2 degrees C. it required 18.23ml of 0.2222 M HCl to titrate. calculate the Ksp for this sample

Answer 1

Given:

Volume of sample = 5 mL Borax (Sodium tetraborate)
Temperature = 49.5 degrees C
Volume of titrant = 18.23 mL
Concentration of Titrant = 0.2222 M HCl

First, set-up a balanced equation:

Na2B4O7*10H2O(borax) + 2 HCl = 2 NaCl + 4 H3BO3 + 5 H2O

Calculate the concentrations of HCl, NaCl, and H3BO3, then solve for the Ksp or Solubility Product Constant:

Ksp = ([NaCl]^2 * [H3BO3]^4) / [HCl]^2