Importance of Salts and Air Dissolved in Water

Q.

Explain azeotropic refrigerants.

Q.

Why are concentric circles formed on the surface of a watch glass after water is evaporated from it?

1. Water evaporates in a circular fashion.

2. Water contains dissolved salts that are left behind in concentric circles after evaporation.

3. Water does not completely evaporate when left on a watch glass.

4. Water evaporates and condenses on the watch glass to form concentric circles.

Q.

Rainwater contains large amount of dissolved salts

1. True
2. False

Q.

Find the odd one out. Give a reason for your answer.

1. Spring water

2. distilled water

3. river water

4. rainwater