Question

Calculate the mass and number of oxalic acid molecules in 100ml of 0.01 M oxalic acid solution.

Answer 1

Normality = molarity * basicity

basicity of Oxalic acid (COOH)2 = 2

Therefore, 0.02 N Oxalic acid = (0.02)/2 M Oxalic acid

i.e, molarity of 0.02 N Oxalic acid = 0.01 M Oxalic acid

Now. 1000 ml contains 0.01M of Oxalic acid therefore,

100 ml will contain (0.01*100) /1000 = 0.001 Moles of Oxalic acid

Therefore no. of molecules = 6.022 * 10^23 * 0.001

= 6.022 * 10^20 molecules of Oxalic acid

Moles = Mass/Molar mass

Mass = Moles * Molar mass

= 0.001 * 126

= 0.126g