Question

An equimolar solution of ${\text{NaN}}{{\text{O}}_{\text{2}}}$ and ${\text{HN}}{{\text{O}}_{\text{2}}}$ can act as :
A. Strong Reductant
B. Strong Oxidant
C. Buffer Solution
D. None of these

Answer 1

Hint: To know whether ${\text{NaN}}{{\text{O}}_{\text{2}}}$ and ${\text{HN}}{{\text{O}}_{\text{2}}}$ makes an equimolar solution or not, we should whether both the compounds are strong or weak base and acid respectively. Once we know that, we can analyse the characteristics to term them as one among the mentioned options.

Complete step-by-step answer:
We all know that, ${\text{HN}}{{\text{O}}_{\text{2}}}$ is a weak acid. ${\text{HN}}{{\text{O}}_{\text{2}}}$ partially dissociates in the aqueous solution. Here is the equation of the dissociation of ${\text{HN}}{{\text{O}}_{\text{2}}}$ :


${\text{NaN}}{{\text{O}}_{\text{2}}}$ is the example of a salt, which is formed by the reaction between weak acid and strong base. The weak acid is ${\text{HN}}{{\text{O}}_{\text{2}}}$ and the strong base is NaOH. Here is the structure of ${\text{NaN}}{{\text{O}}_{\text{2}}}$:


The equation for the formation of ${\text{NaN}}{{\text{O}}_{\text{2}}}$ is :
$\text{HN}{{\text{O}}_{\text{2}}}\text{+NaOH}\xrightarrow{{}}\text{NaN}{{\text{O}}_{\text{2}}}\text{+}{{\text{H}}_{\text{2}}}\text{O}$
We know, a buffer solution is an aqueous solution consisting of a mixture of a weak acid and its conjugate base or vice versa. Its pH changes very little when a small amount of strong acid or base is added to it. Therefore, an equimolar solution of ${\text{NaN}}{{\text{O}}_{\text{2}}}$ and ${\text{HN}}{{\text{O}}_{\text{2}}}$ can act as a buffer solution.
 So the correct answer is Option C.

Note: Buffer solutions have pH more than 7, are known as acidic buffer solutions.
A buffer is a solution that can resist pH change upon the addition of acidic or basic components. It is able to neutralize small amounts of added acid or base, does maintain the pH of the solution relatively stable. This is important for the processes and or reactions which requires specific and stable pH ranges.