Question

What species are characteristics of acid and of bases in the following solvents:
a.liquid ammonia, anhydrous acetic acid
b.anhydrous nitric acid
c.anhydrous $HF$
d.anhydrous perchloric acid
e.anhydrous sulphuric acid
f.dinitrogen tetroxide

Answer 1

Hint: We are given six solvents. We have to identify the molecules or compounds which display the characteristics of acid and base. We will use the concept of Autoionization to decide which solvent has characteristics of acid or base. Autoionization is a process in which an molecule or atom in excited state spontaneously gives an electron from one of its outer shells increasing its charge or going from electrically neutral to single ionized state.

Complete answer:
Autoionization probably occurs in solvents only in which strongly solvated protons are donated.
Let’s see the first option, reactions according to autoionization
$2N{H_{3\;}}\left( {\text{l}} \right)\; \rightleftharpoons \;N{H_4}^ + \; + \;N{H^{2 - }}\;\;$(ammonia)
$2C{H_3}COOH\; \rightleftharpoons \;C{H_3}CO{O^ - }\; + \;C{H_3}COO{H_2}^ + $ (Acetic acid)
Acetic acid behaves as a strong acid in liquid ammonia
Let’s see the second option, reaction according to autoionization
$2HN{O_3}\; \rightleftharpoons \;N{O_2}^ + \; + \;N{O_3}^ - \; + \;{{\text{H}}_2}{\text{O}}$ (Nitric acid)
Nitric acid dissociated to give nitrate ions and nitronium ions. It shows both acidic and basic properties
Let’s see the third option, reaction according to autoionization
$3HF\; \rightleftharpoons \;{{\text{H}}_2}{{\text{F}}^ + }\;\; + \;H{F_2}^ - $ (Hydrogen fluoride)
It forms a very strong acidic solution.
let’s see the next option, reaction according to autoionization
$2HCl{O_4}\;\; \rightleftharpoons \;\;{{\text{H}}_2}Cl{O_4}^ + \;\; + \;Cl{O_4}^ - $
Perchloric acid is a very strong acid it dissociates to give perchlorate ion which is a weak base.
let’s see the next option, reaction according to autoionization
$2{{\text{H}}_2}S{O_{4\;}}\; \rightleftharpoons \;{{\text{H}}_3}S{O_4}^ + \; + \;HS{O_4}^ - $
It is a strong acid which gives a weak base. It can behave as both acid and base in an acid-base reaction.
Let’s see the last option, reaction according to autoionization
${{\text{N}}_2}{{\text{O}}_4}\;\; \rightleftharpoons \;N{O^ + }\; + \;N{O_3}^ - $
It is acidic in nature; it is an acidic anhydride of nitric acid.

Note:
Definitions of acid and base according to autoionization
Acid: An acid is a solvent cation or any chemical substance that increases the quantity of solvent cations generally produced by solvent autoionization.
Base: A base is a solvent anion or any chemical substance that increases the quantity of solvent anion generally produced by solvent autoionization.