Question 13.
Give scientific reasons.
While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, the concentrated sulphuric acid is added slowly to water with constant stirring.
Answer:
When concentrated sulphuric acid is diluted with water, a very large amount of heat is released. It is very dangerous and can cause accident.
⇒ To avoid this, a required amount of water is taken in a beaker.
⇒ Small quantity of sulphuric acid is added into the water.
⇒ Constant stirring has to be done to decrease the releasing heat.
⇒ As a result, only a small amount of heat is released.
Note: In chemical labs, it always advised that we should add acid in water, not water in acid.
