Question

Soda lime is a strong base/acid? As CO2 consumes the basic substrate what happens?

a) Soda lime is a strong base, and as CO2 consumes the basic substrate, the pH decreases.
b) Soda lime is a strong acid, and as CO2 consumes the basic substrate, the pH increases.
c) Soda lime is a strong base, and as CO2 consumes the basic substrate, the pH increases.
d) Soda lime is a strong acid, and as CO2 consumes the basic substrate, the pH decreases.

Answer 1

a) Soda lime is a strong base, and as CO2 consumes the basic substrate, the pH decreases. Soda lime is a strong base that decreases in pH when it absorbs and reacts with CO2, forming carbonates, thereby consuming the basic substrate and reducing alkalinity.

Step-by-step explanation:

Soda lime is not an acid but a strong base, typically consisting of a mixture that includes calcium hydroxide (Ca(OH)2) and sodium or potassium hydroxide (NaOH or KOH), which function to absorb CO2. When CO2 is absorbed, it reacts with the strong base to form carbonates and bicarbonates. This process removes hydroxide ions (OH−) from the solution, which essentially converts the strong base into a weaker one, and lowers the concentration of OH− ions. Following Le Chatelier's principle, the equilibrium shifts to decrease the high concentration of CO2. The overall reaction reduces the pH level as more CO2 is consumed.

Thus, the correct answer to the question is a) Soda lime is a strong base, and as CO2 consumes the basic substrate, the pH decreases.