The charge on colloidal particles is due to

Which of the following is a microbial insecticide?

Which of the following compounds is consumed during the preparation of $Na_2CO_3$ by Solvay's process?

What is the product obtained from the oxidation of isopropyl alcohol?

If a change in current of $0.01 ~A$ in one coil produces a change in magnetic flux of $2 \times 10^{-2} ~Wb$ in the other coil,then the mutual inductance of the two coils in henry is (in $~H$)

For the reactions:
$2NO + O_2 \rightleftharpoons 2NO_2 ; K_1$
$4NO + 2Cl_2 \rightleftharpoons 4NOCl ; K_2$
$NO_2 + 1/2 Cl_2 \rightleftharpoons NOCl + 1/2 O_2 ; K_3$
where $K_1, K_2, K_3$ are equilibrium constants,then $K_3^2$ is equal to: