Question

The pH of a carbonated drink is ___________.
(A) less than 7
(B) more than 7
(C) equal to 7
(D) approximately $7.8$

Answer 1

Hint: pH is a scale used to identify acidity or basicity of an aqueous solution. Acidic solutions have lower pH value and basic or alkaline solutions have a higher pH value.

Complete Step by step solution:
The pH can be less than zero for very strong acids and greater than fourteen for very strong bases. At ${25}^{\circ }$ C, solutions with pH less than 7 are acidic and solutions with greater than 7 pH are basic. More precisely pH is negative of base 10 logarithm of hydrogen ion that is $H^{+}$ concentration. The concept of pH was introduced by Danish chemist Soren Dedec in the year 1909.
In carbonated drinks, there is a presence of carbon dioxide and water. Carbon dioxide reacts with water as the following reaction,
 $C{O}_2+H_{2}O\to H_{2}C{O}_3$
where $C{O}_2$ is carbon dioxide, $H_{2}O$ is water and $H_{2}C{O}_3$ is carbonic acid.
Carbonic acid formed here is an acid and it releases $H^{+}$ ion and forms bicarbonate ion.
 $H_{2}C{O}_3\to H^{+}+HC{O_3}^{-}$
As carbonic acid releases $H^{+}$ ion, pH of carbonic acid decreases. And it becomes less than 7 due to an increase in concentration of $H^{+}$ ion. The pH of carbonated drinks is around 3 to 4.

Note:
In ocean acidification, carbonic acid is an important component. Its structure is

Carbonic acid plays an important role in the bicarbonate buffer system and it is used to maintain acid base homeostasis. Carbonic acid is also widely used in production of soft drinks and other bubbly beverages.