Which of the following is the strongest acid?

Urea is preferred to ammonium sulphate as a nitrogenous fertilizer because

Which of the following is a Lewis acid?

$CH_3COOH_{(aq)} + H_2O_{(l)} \rightleftharpoons H_3O^{+}_{(aq)} + CH_3COO^{-}_{(aq)}$. Between $H_2O$ and $CH_3COO^{-}$,which one is the weaker base?

Match the following acids in List-$I$ with their respective acid dissociation constants $(K_a)$ in List-$II$:

List-$I$ (Acid)	List-$II$ $(K_a)$
$A$. Phenol	$I$. $1 \times 10^{-13}$
$B$. Benzoic acid	$II$. $3.0 \times 10^{-8}$
$C$. $HClO$	$III$. $1.0 \times 10^{-10}$
$D$. $CH_3COOH$	$IV$. $6.5 \times 10^{-5}$
	$V$. $1.75 \times 10^{-5}$

The correct match is:

The $pK_a$ values in $H_2O$ of picric acid,acetic acid,and phenol are in the order: