Descriptors: Descriptors are the symbols used to show the transformations from one to another. Descriptors are usually used between reactants and products or between two different structures of the same compound.
Different types of descriptors are shown below:
A. Double headed arrow: Double headed arrow is shown between the two canonical structures (resonance structures).
B. Equilibrium symbol: Equilibrium symbol, which favors a forward reaction.
C. Equilibrium symbol: Equilibrium symbol which favors a reverse reaction.
D. Equilibrium symbol: Equilibrium symbol, which favors neither forward nor reverse reaction.
Equilibrium nature: Equilibrium shifts towards less acidic substances that are from lower Pka to higher Pkaof the substances.