When orthophosphoric acid is heated to `600^(@)C` the product formed is

Options

A. `HPO_(3)`
B. `H_(3)PO_(3)`
C. `P_(2)O_(5)`
D. `PH_(3)`

Answer

1

Explanation

When heated at `250^(@)C` it yields pyrophosphoric acid:
`2H_(3)PO_(4) overset(250^(@)C)rarrH_(4)P_(2)O_(7)+H_(2)O`
On further heating, it yields metaphosphoric acid.
`H_(3)PO_(4)overset(Delta)underset(600^(@)C)rarrHPO_(3)+H_(2)O`
or `H_(4)P_(2)O_(7) overset(Delta)rarr2HPO_(3)+H_(2)O`
It yields `P_(4)O_(10)`, when strongly heated at red heat:
`4H_(3)PO_(4)overset(Delta)rarrP_(4)O_(10)+6H_(2)O`