The conjugate base of hydrazoic acid $(N_3H)$ is .......

Arrange $NH_4^+$,$H_2O$,$H_3O^+$,$HF$,and $OH^-$ in increasing order of their acidic strength.

Match the following:

List-$I$ (Acid)	List-$II$ ($K_a$ - Ionization Constant)
$A$. $HCN$	$I$. $6.8 \times 10^{-4}$
$B$. $H_2C_2O_4$	$II$. $8.9 \times 10^{-8}$
$C$. $H_2S$	$III$. $4.9 \times 10^{-10}$
$D$. Niacin	$IV$. $5.6 \times 10^{-2}$
	$V$. $1.5 \times 10^{-5}$

The correct match is:

Consider the following reaction involving two acids shown below: formic acid and $HF$.
$K^+F^- + HCOOH \rightleftharpoons HCOO^-K^+ + HF$
Given: $pK_a$ of $HCOOH = 3.8$ and $pK_a$ of $HF = 3.2$.
Which of the following statements about this reaction are true?
$(A)$ Formic acid is the strongest Bronsted acid in the reaction
$(B)$ $HF$ is the strongest Bronsted acid in the reaction
$(C)$ $KF$ is the strongest Bronsted base in the reaction
$(D)$ $KO_2CH$ is the strongest Bronsted base in the reaction
$(E)$ The equilibrium favours the reactants
$(F)$ The equilibrium favours the products
$(G)$ Formic acid has a weaker conjugate base
$(H)$ $HF$ has a weaker conjugate base

Derive $K_w = K_a \times K_b$ and $pK_w = pK_a + pK_b$ for a weak base $B$ and its conjugate acid $BH^{+}$.

The concentration of which ion is decreased when $NH_3$ solution is added?