Question

23.6 lit 0.1 M HCl is completely neutralized by 5 lit NaOH then conc. Of NaOH would be:-
A. 0.472 M
B. 4.72 M
C. 0.0472 M
D. $4.72\times {{10}^{-4}}$ M

Answer 1

Hint: To solve this question we have to use the concept of neutralization reaction which is a type of chemical reaction that takes place between an acid and a base to give salt and water. To find the concentration or volume we have a formula of neutralization that is given as ${{M}_{1}}{{V}_{1}}={{M}_{2}}{{V}_{2}}$ , where M is the concentration and V is the volume.

Complete step by step solution:
From your chemistry lessons you have learned about the neutralization reaction between the acid and base. Neutralization reaction is a type of chemical reaction which takes place between an acid and a base to form water and salt and it involves the combination of ${{H}^{+}}$and $O{{H}^{-}}$ to form the water. Neutralization reaction is given as:
\[Acid+Base\to Salt+water\]
This reaction is generally an acid-base neutralization reaction and the pH of the neutralized solution depends on the acidic strength of the reactant. So, when a strong acid reacts with a strong base there will be no excess of ${{H}^{+}}$ions in the solution and therefore the solution will be neutral and pH of the solution will be 7. Likewise when an weak acid reacts with a strong base then the solution will remain basic and thus the pH of the solution will be greater than 7. In case of strong acid and weak base the solution will have excess of ${{H}^{+}}$ and therefore the solution will be acidic and the pH will be less than 7. And if we take weak acid and weak base then weak acid cannot neutralize weak base and vice-versa.
In this question HCl will behave as a strong acid and NaOH as a strong base which react to give salt and water.
\[HCl+NaOH\to NaCl+{{H}_{2}}O\]
To solve the question related to neutralization we use the formula which is given as:
\[{{M}_{1}}{{V}_{1}}={{M}_{2}}{{V}_{2}}\]……….. (1)
Where, ${{M}_{1}}$= conc. of acid (HCl)
${{V}_{1}}$= Volume of acid
${{M}_{2}}$= conc. of base (NaOH)
${{V}_{2}}$ = Volume of the base.
In the question the conc. of HCl is given as 0.1 M and the volume of HCl is 23.6 lit and the volume of NaOH is given as 5 lit here we have to find the conc. of NaOH. Now put all the values in the equation (1), we will get:
\[23.6\times 0.1={{M}_{2}}\times 5\]
\[\therefore {{M}_{2}}=0.472\,M\]
Therefore the concentration of NaOH will be 0.472 M.

Thus, the correct option will be (A).

Note: Neutralization reaction is only applicable in the case of reaction between an acid and a base. This reaction can be an irreversible or reversible reaction. Neutralization reaction is a type of exothermic reaction because heat is released during the reaction. Neutralization reactions have many applications such as in antacid tablets which are used to neutralize the excess gastric acid produced in the stomach.