$Fe$ is made passive by

The most likely reason for the development of resistance against pesticides in insects damaging a crop is

$y + x^2 = \frac{dy}{dx}$ has the solution

Which process is used for the removal of hardness of water?

The major product of the following reaction is

The correct curve between the magnetic induction $(B)$ along the axis of a long solenoid due to current flow $i$ in it and distance $x$ from one end is: