The efficiency of a boiler is found to decrease when boiler scales are formed.Write the chemistry of scale formation?

The efficiency of a boiler is found to decrease when boiler scales are formed. Suggest a suitable chemical method to prevent the scale formation.

When benzene is treated with chloroine in the presence of sunlight a compound which is commonly used as an insecticide is formed.Write the chemical equation.

A water boiler in a factory burst due to high interior pressure. It was reported that the incident was occurred due to certain dissolved salt in water used. As a chemistry student how will you explain this?