Question

Which of the following is a tetrabasic acid?

• A. Orthophosphoric acid
• B. Hypophosphorus acid
• C. Metaphosphoric acid
• D. Pyrophosphoric acid

Answer 1

The correct option is D Pyrophosphoric acid

$HO-\underset{O}{\stackrel{\underset{|}{OH}}{\underset{||}{P}}}-O-O-\underset{O}{\stackrel{\underset{|}{OH}}{\underset{||}{P}}}-OH$