Question

I understand that liquid leaked from AA alkaline batteries is an aqueous solution of potassium hydroxide (which is highly alkaline). It becomes potassium carbonate (which is less alkaline than potassium hydroxide but still relatively alkaline) once exposed to air (or, more precisely, to carbon dioxide).I also understand that potassium carbonate becomes potassium bicarbonate (which is mildly alkaline) once exposed to air (or, more precisely, to carbon dioxide).

1. Then, does it mean that an aqueous solution of potassium hydroxide from AA alkaline batteries will first become potassium carbonate and then potassium bicarbonate, if they are left untouched and exposed to air (as in normal life)?
2. If potassium carbonate, which was created by exposing potassium hydroxide to carbon dioxide, were exposed to water, would it become an aqueous solution of potassium hydroxide (which would perhaps be more dilute than the original)? Similarly, if potassium bicarbonate were exposed to water, would it become an aqueous solution of potassium hydroxide (which would perhaps be even more dilute than the original)?

Answer 1

1. An aqueous solution of potassium hydroxide from AA alkaline batteries will first become potassium carbonate and then potassium bicarbonate if left exposed to air. 2. Potassium carbonate and potassium bicarbonate will not revert back to an aqueous solution of potassium hydroxide if exposed to water.

Step-by-step explanation:

1. Yes, an aqueous solution of potassium hydroxide from AA alkaline batteries will first become potassium carbonate and then potassium bicarbonate if left untouched and exposed to air. When potassium hydroxide reacts with carbon dioxide in the air, it forms potassium carbonate (K₂CO₃). Upon further exposure to carbon dioxide, potassium carbonate reacts to form potassium bicarbonate (KHCO₃).

2. If potassium carbonate, which was created by exposing potassium hydroxide to carbon dioxide, were exposed to water, it would not become an aqueous solution of potassium hydroxide. Potassium carbonate is only soluble in water to a very limited extent.

Similarly, if potassium bicarbonate were exposed to water, it would not become an aqueous solution of potassium hydroxide. Potassium bicarbonate is already dissolved in water when in the form of an aqueous solution.