Classify if H^3PO^4 is a strong or weak acid, or strong or weak base, or salt?

Expert Answers

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H3PO4 is commonly known as Phosphoric acid. As the name suggests, this compound is an acid. Generally an acid, is a proton donor, has a pH below 7, neutralizes base and turns blue litmus paper to red. This also means that in a solution (in water) H3PO4 produces Hydronium ions (H3O+ ions).

The chemical equation for the dissociation of Phosphoric acid (H3PO4) in the solution can be written as:

H3PO4(s)   + H2O(l)  --->H3O+(aq) + H2PO4−(aq)

H2PO4−(aq)+ H2O(l) <--->H3O+(aq) + HPO42−(aq) 

HPO42−(aq)+ H2O(l) <---> H3O+(aq) +  PO43−(aq) 

**H3PO4 contains 3 H's that can be protonated.

 

The first ionization (protonation) of Phosphoric acid can only be considered as strong acid.

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