When sodium hydroxide (NaOH) reacts with carbon dioxide (CO2), it forms sodium carbonate (Na2CO3) and water (H2O). This is a neutralization reaction where a base (NaOH) reacts with an acidic oxide (CO2) to form salt and water.

Here's the balanced chemical equation:

2 NaOH + CO2 → Na2CO3 + H2O

Here's a breakdown of what happens:

* Step 1: Carbon dioxide dissolves in water to form carbonic acid (H2CO3). This is a weak acid.

CO2 + H2O ⇌ H2CO3

* Step 2: The carbonic acid then reacts with sodium hydroxide in a neutralization reaction.

H2CO3 + 2 NaOH → Na2CO3 + 2 H2O

Overall reaction:

The overall reaction combines these two steps to form sodium carbonate and water:

2 NaOH + CO2 → Na2CO3 + H2O

Practical Applications:

This reaction is used in a variety of applications, including:

* Carbon dioxide scrubbing: Sodium hydroxide is used to remove CO2 from air or other gas streams. This is important in industrial processes, such as in power plants, where CO2 emissions are a concern.

* Making sodium carbonate: The reaction is used to produce sodium carbonate, an important industrial chemical used in glass making, detergents, and other products.

Important Note:

* The reaction is exothermic, meaning it releases heat.

* If the reaction is carried out in a closed container, the pressure can build up as CO2 is consumed.

* The reaction is typically carried out in aqueous solution, where sodium hydroxide is dissolved in water.