Question

Give the basicity of $H_3PO_4$ .

Answer 1

Basicity is the quality of being a base (not an acid). A base may be a substance which will accept hydrogen ions in water and may neutralize an acid. Basicity is also measured on the scale called the PH. On this scale, a pH value of seven is neutral, and a pH value of quite 7 to 14 shows increasing basicity.

Complete answer:
In Ortho phosphoric acid $H_3PO_4$ , three hydrogen atoms, one phosphorus atom and 4 oxygen atoms are present. During this compound, three hydrogen atoms are joined with three oxygen atoms. Therefore, the worth of basicity is 3.
Basicity means number of replaceable hydrogen atoms. $H_3PO_4$ 3H+ + $PO_4$ - For the hydrogen to be acidic it must be attached to the strong electronegative atom which is attached to the three oxygen. Hence, the basicity of $H_3PO_4$ is 3.
The basicity of Ortho phosphoric acid in the is 3. Basicity is the number of acid hydrogen atoms within the molecule. For hydrogen to be acidic, it also must be attached to a strongly electronegative atom like oxygen or fluorine.
Basicity of an acid refers to the amount of replaceable hydrogen atoms in one molecule of the acid. As you'll see within the above image of the structure of $H_3PO_4$ , there are 3 OH's attached.

Note:
The OH group present is ionizable because the H atom is attached to a highly electronegative atom O (oxygen). Ortho phosphoric acid features a formula $H_3PO_4$ . In this, the phosphorus features a +5 oxidation number.