Which acid is present in tomatoes?

Match the given ionisation constant values with the corresponding acids.

$A$. $HI$	$(i)$ $3.2 \times 10^9$
$B$. $HF$	$(ii)$ $3.5 \times 10^{-4}$
$C$. $HCl$	$(iii)$ $1.3 \times 10^6$
$D$. $HBr$	$(iv)$ $1.0 \times 10^9$

The correct match is:

In the reaction $HNO_3 + H_2O \rightleftharpoons H_3O^{+} + NO_3^{-}$,the conjugate base of $HNO_3$ is = .......

What is the conjugate acid of $HPO_4^{2-}$?

Aqueous ammonia is used instead of aqueous $NaOH$ solution to precipitate $Al^{3+}$ ions as $Al(OH)_3$ because .................

Observe the following species: $AlCl_3, NH_3, H^{+}, Co^{3+}, OH^{-}, H^{-}, Mg^{2+}, BF_3, Cl^{-}$. How many Lewis bases are present in the above list?