Question

How can i calculate eqivalent weight of oxalic acid

Answer 1

do you know the molecular formula of oxalic acid?

Answer 2

http://chem-guide.blogspot.com/2010/03/equivalent-weight-of-elements-and.html


Equivalent weight of an acid
The valence factor of an acid is equal to its basicity. The basicity of an acid is equal to furnishable hydrogen ion (proton) in its aqueous solution. Importantly, basicity is not same as the number of hydrogen atoms in acid molecule. Consider acetic acid (CH3COOH). It contains 4 hydrogen atoms in it, but only 1 furnishable hydrogen ion. As such, basicity of acetic acid is 1. With this background, we define equivalent weight of an acid as :

Equivalent weight,E=

Molecular weight of acid Basicity
Basicity of sulphuric acid is 2. Hence, equivalent weight of sulphuric acid (H2SO4) is (2X1 + 32 + 4X16)/2 = 98/2 = 49. Similarly, basicity of oxalic acid is 2. Hence, equivalent weight of oxalic acid (H2C2O4 ) is (2X1 + 2X12 + 4X16)/2 = 90/2=45.

Phosphorous based acids like phosphoric acid (H3PO4 ), phosphorous acid (H3PO3) and hypo-phosphorous acid (H3PO2) need special mention here to understand their basicity. The structures of three acids are shown here. From the structure, it appears that these compounds may furnish OH ions, but bond strengths between phosphorous and oxygen (P-O) and phosphorous and hydrogen (P-H) are stronger than between oxygen and hydrogen (O-H) in –OH group. As such, these molecules release hydrogen ions from –OH group and behave as acid. Clearly, basicities of phosphoric acid (H3PO4), phosphorous acid (H3PO3) and hypo-phosphorous acid (H3PO2) are 3, 2 and 1 respectively.