Question

Calculate the equivalent mass of (i) Sulphate ion (ii) Phosphate ion.

Answer 1

(i) Sulphate ion (SO₄^2-). 

Equivalent mass of Sulphate = (Molar mass of sulphate ion) / Charge

= (32 + 64) / 2

= 96/2

= 48 g eq^-1

(ii) Phosphate ion (PO₄^3- ) 

Molar mass of Phosphate ion = (Molar mass of phosphate ion) / Charge 

= (31 + 64) / 3

= 95/2

= 31.6 

= 31.6g eq^-1