Question

Determine the average volume of diluted HCl solution required to titrate a 10ml sample of saturated Ca(OH)2 solution in distilled water and determine the [Ca(OH)2] in this solution

Temperature 25 celsius =298.15 kelvin

Volume of Ca(OH)2= 10 ml

Volumes of HCl solution used: 26.6ml, 23.5ml, 29.5ml, 23.2ml, 18.3ml, 8.6ml, and 13ml

HCl 1.2M

Answer 1

Given volumes of 1.2M HCl used is 26.6ml, 23.5 ml, 29.5 ml,23.2 ml,18.3ml, 8.6 ml and 13.0ml

Average volume = 26.6+23.5+29.5+23.2+18.3+8.6+13.0 / 7

{ average = sum of readings / no.of readings}

Average volume = 142.7 / 7 = 20.38 ml

Average volume of diluted HCl required to titrate a 10ml sample of saturated Ca(OH)2 sample is 20.38ml

Now concentration of Ca(OH)2 = T.VxMxM.Wx1000/V

Here, T.V = volume of HCl rundown = 20.38ml(average volume)

M= Molarity of HCl used= 1.2 M

M.W = molecular weight of calcium Hydroxide = 74.09g/mol

V= volume of Ca(OH)2 sample = 10 ml

Therefore, Concentration = 20.38x1.2x74.09x1000 / 10 ppm as Ca(OH)2

= 1811945 / 10 = 181194.5 ppm as Ca(OH)2

= 18.12% as Ca(OH)2