How decreasing order of acidic strength possible for : H 3 PO 2 > H 3 PO 3 > H 3 PO 4 ??

How decreasing order of acidic strength possible for :

                        H3PO2 > H3PO3 > H3PO4 ??

Grade:Upto college level

2 Answers

Tapasranjan Das
19 Points
12 years ago

Hi mainak

if we look at the structure of those three we can easily find that basicity for

1.  H3PO2   is 1

2. H3PO3  is 2   and

3. H3PO4    is  3

and since basic character is increasing hence acidic character is decreasing.....for the structures go through any inorganic chemistry book

deepak askiitiansExpert-iit
19 Points
12 years ago



all oxoacids of phosphorous has typically two types of bonds i.e. P-H& P-OH

only P-OH is ionisable,H3PO2 has only one P-OH bond it will furnish all its hydrogen ions in a single step.

other are dibasic&tribasic  which do it in steps.

hence, Ka for h3po2  is highest &hence strongest acid.

if you like my answer ,please approve it.

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