Question

Fill in the blanks-
\[NaHC{O_3}\] is a salt of a _______________ acid with a ______________ base.
A. strong, strong
B. strong, weak
C. weak, strong
D. weak, weak

Answer 1

Hint: Here we will proceed by defining the term sodium bicarbonate \[\left( {NaHC{O_3}} \right)\] and then we will be discussing the nature of \[NaHC{O_3}\] and how it reacts when it dissolved in water and hence to obtain the required answer of our given problem.

Complete step-by-step answer:
Sodium bicarbonate: Sodium bicarbonate, commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula \[NaHC{O_3}\]. It is a salt composed of a sodium cation and a bicarbonate anion. Sodium bicarbonate is a white solid that is crystalline, but often appears as a fine powder.
An aqueous solution of sodium bicarbonate would be having a pH value above 7, whatever its concentration.
When sodium bicarbonate is put in water, it dissolves and the following ions are present in water at this stage.
\[{H^ + },HCO_3^ - ,N{a^ + }{\text{ and }}O{H^ - }\]
\[HCO_3^ - \] is the conjugate base of carbonic acid which is weak. Hence it immediately forms carbonic acid by reacting with \[{H^ + }\] due to hydrolysis. Hence water now contains excess of \[O{H^ - }\] ions leading to its basic nature.
Also, the salt is called an acidic salt because not all the H atoms of carbonic acid were replaced by sodium atoms.
Sodium bicarbonate \[\left( {NaHC{O_3}} \right)\] is a salt of weak acid \[\left( {{H_2}C{O_3}} \right)\] with strong base \[\left( {NaOH} \right)\] which is given as \[{H_2}C{O_3} + NaOH \to NaHC{O_3} + {H_2}O\].
Thus, the correct option is C. weak, strong

Note: Sodium bicarbonate is an antacid used to relieve heartburn, sour stomach, or acid indigestion by neutralizing excess stomach acid. When used for this purpose, it is said to belong to the group of medicines called antacids.