Q96P - Chemistry: Molecular Nature Of Matter And Change

Question

Assuming acid strength relates directly to a number of $\mathbf{O}$ atoms bonded to the central atom, rank ${\mathbf{H}}_{\mathbf{2}}{\mathbf{N}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{2}}$  $[\mathrm{or} {\left(\mathrm{HON}\right)}_2]$; ${\mathbf{HNO}}_{\mathbf{3}}\mathbf{ }\left(\mathrm{or} {\mathrm{HONO}}_2\right)$; and ${\mathbf{HNO}}_{\mathbf{2}}\left(\mathrm{or} \mathrm{HONO}\right)$ in order of decreasing acid strength.

Step-by-Step Solution

Answer

Definition of Acids

Acids are the chemical species or compounds which give ${\mathbf{H}}^{\mathbf{+}}$in their aqueous solution, or we can say that the species which donates proton are called acid.

Different factors affect the acidic strength, like electronegativity, oxidation number, etc.

Electronegativity $\propto$ acidity

Oxidation number $\propto$ acidity

Order of acidity of given acids

Acidic strength is increased with an increase in the number of oxygen bonded to a central atom as the number of oxygen atoms in ${\mathrm{HNO}}_3$ are more so that it gives a large number of ${\text{H}}^{+}$ in the aqueous solution. In ${\mathrm{HNO}}_2$ there is only one hydrogen that can be donated while in ${\left(\text{HNO}\right)}_{\text{2}}$ two hydrogens that can be donated, so that ${\left(\text{HNO}\right)}_{\text{2}}$ is more acidic than ${\text{HNO}}_{\text{2}}$.