Mesomeric effect stabilizes the anion formed when hydrogen of the the -OH group in the 2-nitrophenol is lost. This mesomerism is most pronounced at the 2 and 4 position.
Stronger bases have more available lone pair of electrons. The lone pair of electrons in aniline is delocalized over the ring. Hence it is unavailable for protonation while the lone pair on benzyl amine is available for protonation
Diethylamine is a stronger base because it has a balance of both inductive electron donation by alkyl groups, and solvation of the conjugate acid unlike triethylamine. Hence Diethylamine is a stronger base than triethylamine
decrease in temperature , decreases the kinetic movements of the gase molecules as a result decreases the frequency of collisions between gas molecules A and B consequently decreases the rate of reactions of gases A and B