Question

Pyridine, an organic base, has the formula C5H5N , has a KB = 1.78 x 10–9.

Write the equilibrium formed when C5H5N dissolves in water.

Identify the conjugate acid of C5H5N and calculate its KA.

Answer 1

C5H5NH⁺

pKb = -log (1.78 x 10^–9) = 8.75

pKa + pKb = 14

pKa = 14 - 8.75 = 5.25

Ka = 5,62x10^-6