Explanation Content

Respirometer | NCERT Class 7

Science · Class 7

Add few drops of Bromothymol blue in water. Now make Calcium Hydroxide solution by dissolving given lime in water. Put few drops of the calcium hydroxide solution in the bromothymol - water solution and observe the colour change. Now squeeze few drops of lemon juice in the solution to see a colour change. This is how bromothymol blue solution is used to check the pH. Make the solution alkaline again and now blow in it through a straw and count the number of breaths you require to change the colour. Repeat the experiment after doing some exercise and observe if there is a change in the number of breaths required to change the colour.