The strongest Bronsted base among the following anions is

In the following reaction:
$[Al(H_2O)_6]^{+3} + HCO_3^{-} \rightleftarrows [Al(H_2O)_5OH]^{+2} + H_2CO_3$
$(A)\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad(B)\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad(C)\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad(D)$
Which species behave as Bronsted-Lowry acids?

The dissociation constant values of three acids $A$,$B$ and $C$ are $1.8 \times 10^{-5}$,$1.5 \times 10^{-4}$ and $5.2 \times 10^{-8}$ respectively. The correct order of increasing basic nature of their conjugate bases is $-$

Classify the following species into Lewis acids and Lewis bases and show how these act as such:
$(a) HO^{-}$
$(b) F^{-}$
$(c) H^{+}$
$(d) BCl_{3}$

Which acid among the following has the highest $pK_a$ value?

The $K_{a}$ values of $A$,$B$,and $C$ are $1.8 \times 10^{-4}$,$5 \times 10^{-10}$,and $3 \times 10^{-8}$ respectively. The correct order of their acidic strength is