1. What is the effect of adding salt to boiling water?

2. Providing excess food for fish in an aquarium is a threat to its survival. Justify.

3. Soap decrease the surface tension of water.

a. What is surface tension?

b. How does the decrease in surface tension benefit washing of clothes?

a. The unbalanced attractive force on the surface of a liquid causes the liquid surface behaves like a stretched membrane. This is surface tension

b. When we add soap to water it reduces the surface tension of water and water can enter into the fine threads of the fabric.