Which of the following statement/s is/are correct about weak acids in aqueous solutions? I. When $$pH = pK_a$$ of a monoprotic acid, 50 percent of the acid is ionised II. If $$pH = pK_{a2}$$ of a diprotic acid, the average charge of all the ionised species is 0.5 III. When $$pH = pK_a + 1$$, 10 percent of the acid is ionised IV. When $$pH = 7$$, 50 percent of a monobasic acid is ionised

A

I and IV

B

I, II and IV

C

Statements I, II and IV

D

I only