Question

Is H3PO3 a dibasic acid ​

Answer 1

It has three acidic protons (attached to oxygen) and is therefore tribasic. Its salts are called phosphates. But H3PO3, phosphonic acid, has one of the hydrogens directly bound to phosphorus as O=PH(OH)2. This means that only two hydrogens are available to act as acids.

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Answer 2

yes , H3PO3 is a dibasic acid