Explain the following:
A white crust forms on the surface of lime water that has been exposed to the air.

Explain briefly the following: Alveolar air

Give reasons : A white powder is formed on the surface of washing soda crystals when left exposed to atmosphere.

Explain the following: Anhydrous iron (III) chloride turns to a solution when exposed to air.

Explain why do the bodies such as cork or wood float on the surface of water.

Explain the following: In winter, water tank (or ocean) starts freezing from the surface and not the bottom.

Which of the following ion is likely to form white complexes

Oxygen in atmosphere has been formed by:

A point source of light is placed inside water and a thin converging lens of focal length f is placed just outside the surface of water. The image of source is formed at a distance of 50 cm from the surface of water. When the lens is placed just inside the water surface the image is formed at a distance of 40 cm from the surface of water. if focal length of the lens in air is f=(100k)/8 cm, then find the value of k. (given refractive index of lens is 3/2 and that of water is 4/3 and in both cases image is formed inside water for the viewer in air).

Efflorescent substances .....................water when exposed to air.