Which of the following acids forms three series of salts?


H3PO2 is monobasic as it consist of only one OH group.

Structure of H3PO2:


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H3BO3: it does not act as proton donor but behaves as lewis acid. Boric acid does not dissociate in aqueous solution. It can be predicted from its structure that it have 3 OH group. Boric acid first accept one OH- then it liberates one electron per molecule. Therefore it is monobasic.


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H3PO3: it is dibasic as it have two OH group.


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structure of H3PO4:


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It has three OH group therefore it is tri basic. Oxidation state of phosphorous in H3PO4 is +5.


As it has three OH group, it means that it has 3 ionisable hydrogen atoms and hence form three series of salts. These are:


1.NaH2PO4


2. NaHPO4


3. Na3PO4


Hence the correct option is (iii).

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