Question

What is the correct order of acidic strengths of oxides of nitrogen?

• A. ${\mathrm{N}}_2\mathrm{O}>{\mathrm{N}}_2{\mathrm{O}}_5>{\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}$
• B. ${\mathrm{N}}_2{\mathrm{O}}_5>{\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}>{\mathrm{N}}_2\mathrm{O}$
• C. ${\mathrm{N}}_2\mathrm{O}>\mathrm{NO}>{\mathrm{N}}_2{\mathrm{O}}_3>{\mathrm{N}}_2{\mathrm{O}}_5$
• D. ${\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}>{\mathrm{N}}_2\mathrm{O}>{\mathrm{N}}_2{\mathrm{O}}_5$

Answer 1

The correct option is B

${\mathrm{N}}_2{\mathrm{O}}_5>{\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}>{\mathrm{N}}_2\mathrm{O}$

Explanation for the correct option:

(B) ${\mathrm{N}}_2{\mathrm{O}}_5>{\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}>{\mathrm{N}}_2\mathrm{O}$

• The acidity of the oxides of nitrogen increases as the number of oxygen atoms in an oxide increases as oxygen is a very high electronegative atom.
• The oxidation number of nitrogen in ${\mathrm{N}}_2{\mathrm{O}}_5$ is $+5$.
• The oxidation number of nitrogen in ${\mathrm{N}}_2{\mathrm{O}}_3$ is $+3$.
• The oxidation state of nitrogen in $\mathrm{NO}$ is $+2$.
• The oxidation state of nitrogen in ${\mathrm{N}}_2\mathrm{O}$ is $+1$.
• As the oxidation number of the given oxide increases, the acidic strength will also increase.
• Thus, dinitrogen pentaoxide ${\mathrm{N}}_2{\mathrm{O}}_5$ is the most acidic followed by ${\mathrm{N}}_2{\mathrm{O}}_3,\mathrm{NO},{\mathrm{N}}_2\mathrm{O}$ . So, this is the correct option.

Explanation for the incorrect options:

(A) ${\mathrm{N}}_2\mathrm{O}>{\mathrm{N}}_2{\mathrm{O}}_5>{\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}$

• The acidic nature of ${\mathrm{N}}_2\mathrm{O}<{\mathrm{N}}_2{\mathrm{O}}_5$ and not ${\mathrm{N}}_2\mathrm{O}>{\mathrm{N}}_2{\mathrm{O}}_5$ because it does not obey the rule of acidity of the oxides of nitrogen increases as the number of oxygen atoms in an oxide increases as oxygen is a very high electronegative atom.
• Thus, option A is incorrect

(C) ${\mathrm{N}}_2\mathrm{O}>\mathrm{NO}>{\mathrm{N}}_2{\mathrm{O}}_3>{\mathrm{N}}_2{\mathrm{O}}_5$

• The acidic nature of ${\mathrm{N}}_2{\mathrm{O}}_5>{\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}>{\mathrm{N}}_2\mathrm{O}$ as the electronegative nature of oxygen is responsible for the nature of the acidic nature of the oxides of nitrogen
• Thus, the given order of option C is incorrect.

(D) ${\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}>{\mathrm{N}}_2\mathrm{O}>{\mathrm{N}}_2{\mathrm{O}}_5$

• The acidic nature of ${\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}>{\mathrm{N}}_2\mathrm{O}$ but they are not greater than ${\mathrm{N}}_2{\mathrm{O}}_5$ as mentioned in the option
• Thus, the option D is incorrect

Thus, the correct order of acidic strengths of oxides of nitrogen is ${\mathrm{N}}_2{\mathrm{O}}_5>{\mathrm{N}}_2{\mathrm{O}}_3>\mathrm{NO}>{\mathrm{N}}_2\mathrm{O}$ which is an option (B) is correct.