Question

You have four beakers A, B, C and D. Out of A and B one has hard water and the other has soft water. Out of C and D one has soap solution and the other has detergent solution. How would you identify these liquids?

Answer 1

To determine out of A and B which is soft water, add liquid soap to both the water. The one which forms lather and dissolves is soft water and the one which gives scum like matter is hard water as it forms calcium carbonate.

To determine out of C and D which has soap solution and which has detergent, take little hard water and mix into both the jars. The one which forms scum on shaking is soap solution and the one which does not form a scum is detergent solution.