Question

Pure phosphoric acid is very viscous because:
(1) it is a strong acid
(2) it is tribasic acid
(3) it is hygroscopic
(4) it has PO₄^3- groups which are bonded by many hydrogen bonds

Answer 1

Dear Student,

The given phosphoric acid H₃PO₄ is highly viscous and high boiling point due to the presence of hydrogen bonding in concentrated solution hence the answer is Option (4) "it has PO₄^3- groups which are bonded by many hydrogen bonds.

Regards.