What is the increasing order of basic strength for $Cl^{-}, CH_3COO^{-}, OH^{-},$ and $F^{-}$?

In the reaction $NH_3 + H_2O \rightleftharpoons NH_4^+ + OH^-$,water acts as a .......

Phosphoric acid ionizes in three steps with their ionization constant values $K_{a_1}, K_{a_2}$ and $K_{a_3}$ respectively,while $K$ is the overall ionization constant. Which of the following statements are true?
$A.$ $\log K = \log K_{a_1} + \log K_{a_2} + \log K_{a_3}$
$B.$ $H_3PO_4$ is a stronger acid than $H_2PO_4^{-}$ and $HPO_4^{2-}$
$C.$ $K_{a_1} > K_{a_2} > K_{a_3}$
$D.$ $K_{a_1} = \frac{K_{a_3} + K_{a_2}}{2}$
Choose the correct answer from the options given below

$(i)$ $A$ strong acid has a weak conjugate base.
$(ii)$ An acid is an electron pair acceptor.
The above statements $(i)$ and $(ii)$ are:

The conjugate base of $H_3O^{+}$ is

Which of the following is not an acid salt?