For a reaction 2a (aq) + bc (aq) = ab (s) + ac (l), the order of reaction with respect to a is 2 and the overall order of reaction is 2, describe methods to increase the rate of the reaction and explain how the methods work?

As, overall order of reaction is 2 indicates the rate of reaction is only depending on concentration of A and its rate of reaction can be shown as:

R = K [A]^2

So, by increasing the concentration of A, the rate of reaction increases.

Supersaturation. In most cases, it is possible to dissolve more solute by heating up the solution. Even after subsequently cooling the solution, the crystals will stay dissolved. This is called supersaturation – the solute will only crystallize if an additional crystal is added or the solution is disturbed.