Lime water: The correct option is A Ca(OH)2

The correct option is A Ca(OH)2 in water Limewater is the common name for a diluted solution of calcium hydroxide. Calcium hydroxide, Ca(OH)2, is sparsely soluble in water . Pure limewater is clear and colorless, with a slight earthy smell and an alkaline bitter taste of calcium hydroxide. Limewater is prepared by stirring calcium hydroxide in pure water , and filtering off the excess undissolved Ca(OH)2. When excess calcium hydroxide is added to limewater, a suspension of calcium hydroxide ... Full syllabus notes, lecture and questions for NCERT Solutions for Class 7 Science Chapter 2 Exploring Substances: Acidic, Basic and Neutral - Class 7 - Plus excerises question with solution to help you revise complete syllabus for Science (Curiosity) Class 7 - New NCERT - Best notes, free PDF download Procedure: Take a test tube with freshly prepared lime water (calcium hydroxide solution). Blow air through the lime water using a straw and note the time it takes for the solution to turn milky. In another test tube with fresh lime water , use a syringe or pichkari to pass ambient air through the solution and note the time it takes to turn milky. Ans.When air is blown into lime water , carbon dioxide from the air reacts with calcium hydroxide in the lime water . This reaction produces calcium carbonate, which makes the lime water turn milky or cloudy.