Ammonia gas dissolves in water to form $NH_4OH$. In this reaction,water acts as:

The conjugate base of $H_2PO_4^-$ is

The $H^{+}$ ion is a ...... .

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

Which of the following can act both as a Bronsted acid and a Bronsted base?

The correct order of increasing basicity of the given conjugate bases $(R = CH_3)$ is