Question

n-factor of $H_{3}B{O}_3$ in aqueous solution will be :

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is A 1

For acids, n-factor is defined as the number of H+ ions replaced by 1 mole of acid in a reaction. Note that the n-factor for acid is not equal to its basicity; i.e. the number of moles of replaceable H+ atoms present in one mole of acid.

• n-factor of $H_{3}B{O}_3$ = 1
  In $H_{3}B{O}_3$, although all three H are linked to oxygen, yet all 3 H are not replaceable. Here, boron atom is electron deficient, so it acts as a Lewis acid. When $H_{3}B{O}_3$ is added to water, then oxygen atom of H2O through its lone pair attack the boron atom, as follows