How can we easily detect fixed air?

Fixed air, primarily composed of carbon dioxide (CO2), can be easily detected using a simple chemical test. When limewater (a saturated solution of calcium hydroxide) is exposed to CO2, it turns cloudy due to the formation of calcium carbonate. Another method involves using a pH indicator; fixed air can lower the pH of solutions, indicating its presence. Additionally, a gas sensor specifically designed for CO2 can provide quick and accurate detection.