Question

Which of the following compound is a tribasic acid?

• A. $H _{3} PO _{2}$
• B. $H _{3} PO _{4}$
• C. $H _{3} PO _{3}$
• D. $H _{4} P _{2} O _{7}$

Answer 1

Answer: (B)

$H _{3} PO _{4}$

Answer 2

$H _{3} PO _{4}$ is a tetrahedral structure molecule. It contains three $-OH$ group so that three protons can be released. So it acts as a tribasic acid.