I know this is very silly question but I want a full explanation about why does it happen.
When we observe the sky, the Sun, Moon, and stars appear to move from east to west because of the rotation of Earth (so-called diurnal motion).
See the following figure and observe the earth rotation (rotation axis)
Now this is clear because earth rotation is clockwise direction on its axis so a person see the sun, moon etc rise in the east and move towards west.
Because of the speed at which the earth and the moon move relative to the sun, a total solar eclipse can never last more than how long?