Explain the following in one or two sentances only :
"Orthophosphorous acid is not a tribasic acid".

Orthophosphoric acid is

A tribasic acid is

Which is a tribasic acid?

Explain the following in one or two sentence only: 'Phenol is an acid, but it does not react with sodium bicarbonate'.

Which is tribasic acid?

Which of the following will be obtained on heating orthophosphorous acid ?