when an indigestion tablet is placed in water, carbon dioxide is given off.

describe the test for carbon dioxide.

The test for carbon dioxide involves using limewater (calcium hydroxide solution), which is commonly used to detect the presence of carbon dioxide gas. Here's a step-by-step description of the test:

1. Prepare a small amount of limewater: Limewater is a clear, colorless solution made by dissolving calcium hydroxide (Ca(OH)2) in water. You can obtain calcium hydroxide from a chemical supplier or prepare it by mixing calcium oxide (quicklime) with water and allowing it to settle before using the clear liquid on top.

2. Collect the gas: To perform the test, you need to collect the gas evolved when the indigestion tablet reacts with water. Place the tablet in a container, and add water to facilitate the reaction. As the tablet dissolves, carbon dioxide gas will be released.

3. Bubble the gas through the limewater: To test for carbon dioxide, take a small amount of the gas evolved (you can use a test tube or a glass pipette) and bubble it through the limewater. To do this, insert one end of a tube or pipette into the container with limewater, and gently blow or allow the gas to escape into the limewater.

4. Observation of the result: If carbon dioxide is present, a chemical reaction will occur between carbon dioxide and calcium hydroxide in the limewater. This reaction will produce a precipitate called calcium carbonate, which is insoluble and appears as a cloudy or milky white substance in the limewater. The cloudiness indicates the presence of carbon dioxide.

It's important to note that the reaction may take a few moments to occur, so it's recommended to wait and observe the limewater for any changes for a little while.

So, in summary, to test for carbon dioxide, collect the gas and pass it through limewater. If a cloudy or milky white precipitate forms, it indicates the presence of carbon dioxide.