Activity 1.4 Ncert Science class 10
Brief Procedure: This activity asks to put some quick lime (CaO) into the water and observe the reaction.
Observation: Beaker feel hot after adding water
Explanation: Quick lime reacts with water to form slaked lime. The process is exothermic and releases heat.
CaO(s) + H20(l) → Ca(OH)2(aq) + Heat
Application in whitewashing: Slaked lime reacts with the carbon dioxide present in the air. It forms Calcium carbonate which is a shiny compound. For example, Marble used in the home is also the same. So we use slaked lime as whitewash paint in home walls. After two to three days slaked lime convert to carbonate which gives the wall a shiny surface.
Ca(OH)2(aq) + CO2(g) ——–> CaCO3(s) + H20(l)
Another fact: We all know human, and animals absorb oxygen from air and emit carbon dioxide. When we blow air from the mouth into slaked lime solution using a tube, an insoluble precipitate of calcium carbonate forms. This phenomenon confirms the presence of C02 in our breath. Activity 6.4 Life processes.