Question

Bicarbonate ion is an example of a

a. an acid
b. a base
c. an acidic salt
d. a basic salt
e. an amphoteric substance

Answer 1

The bicarbonate ion is an amphoteric substance because it can act as both an acid and a base, able to either accept or donate a proton. So the correct answer is e.

Step-by-step explanation:

The student asked whether the bicarbonate ion is an example of an acid, a base, an acidic salt, a basic salt, or an amphoteric substance. To answer this, we must look at the behavior of bicarbonate in solutions. The bicarbonate ion (HCO3-) can both accept and donate a hydrogen ion (H+), depending on the circumstances. When it accepts a proton (H+), it acts as a base, and when it donates a proton, it acts as an acid. This dual behavior makes bicarbonate an amphoteric substance, capable of acting as both acid and base.

Answer 2

It is both. We normally think of it as a base because it raises the pH of water by accepting a proton,

HCO3- + H2O <-----> H2CO3 + OH-

but if you add bicarbonate to a strongly basic solution, it actually lowers the pH by donating a proton.

HCO3- + OH- <------> CO3(2-) + H2O. That's why it is an amphoteric substance