Question

What does soda water contain?
(A). Carbonic acid
(B). Sulphuric acid
(C). Carboxylic acid
(D). Nitrous acid

Answer 1

Hint: On opening a bottle of soda, the fizz that comes out of the soda bottle is nothing but carbon dioxide which has been dissolved in the soda and kept under pressure.

Complete step-by-step solution -

Soda water is also known as carbonated water and it contains carbonic acid and thus option A is correct. Now, let us understand how soda water is created.

• • We can get carbonated water in various forms such as sparkling water, seltzer water and of course soda water. All these forms of carbonated water contain a main essential ingredient which is carbon dioxide.

• • Carbon dioxide is infused into the water under very high pressure and when it dissolves in water it forms a very weak acid known as carbonic acid.

${ H }_{ 2 }{ O }_{ \left( l \right) }+C{ { O }_{ 2 } }_{ \left( g \right) }\overset { High\quad Pressure }{ \longrightarrow } { H }_{ 2 }{ C{ O }_{ 3 } }_{ \left( l \right) }$

• • When you open a soda water bottle you will notice an effervescence or a fizz of bubbles. This happens because on opening the bottle of soda water, the pressure decreases rapidly. So, the carbonic acid breaks down into water and carbon dioxide is released.

${ H }_{ 2 }{ C{ O }_{ 3 } }_{ \left( l \right) }\overset { Pressure\quad Released }{ \longrightarrow } { H }_{ 2 }{ O }_{ \left( l \right) }+C{ { O }_{ 2 } }_{ \left( g \right) }\uparrow$

Note: Do not confuse carbonic acid with carbolic acid. As we have seen that carbonic acid is ${ H }_{ 2 }{ C{ O }_{ 3 } }$ but carbolic acid is chemically known as phenol ${ C }_{ 6 }{ H }_{ 5 }-OH$. Carbolic acid is used as an antiseptic for ages and in many rural parts, it is used in households to stop snake infestation.