Questions

Kachchh district is the largest in India in terms of territorial extent, located in the state of Gujarat.
The second largest district is Leh in Jammu & Kashmir.

Orographic precipitation or Rain produced when moist air is lifted as it moves over a mountain range. As the air rises and cools, orographic clouds form and serve as the source of the precipitation, most of which falls upwind of the mountain ridge.

Some also falls a short distance downwind of the ridge and is sometimes called spillover. On the lee side of the mountain range, rainfall is usually low, and the area is said to be in a Rain Shadow. 

Chromium is the chemical element that is used as a shiny metal on the automobile bodies especially for trim.

Here in the given puzzle,

2 x (2 + 2) = 8

3 x (3 + 3) = 18

4 x (4 + 4) = 32

5 x (5 + 5) = 50

Similarly,

6 x (6 + 6) = 72.