Question

What is the volume of 0.1 N dibasic acid sufficient to neutralize 1g of a base that furnishes 0.04 mole of OH in an aqueous solution?
A. 400 ml
B. 600 ml
C. 200 ml
D. 80 ml

Answer 1

Hint- To solve this question, we use the basic theory of law of equivalence. According to the law of equivalence, whenever two substances react, the equivalents of one will be equal to the equivalents of other and the equivalents of any product will also be equal to that of the reactant.

Complete answer:
Formula used: Normality of base = $\dfrac{{{\text{molar concentration}}}}{{{\text{n - factor}}}}$
Normality (N) = $\dfrac{{{\text{Number of equivalents of a solute}}}}{{{\text{Volume of solution in litre}}}}$

We need to apply law of equivalence in this question-
As given in question,
We have-
Normality of acid = 0.1
Normality of base = $\dfrac{{{\text{molar concentration}}}}{{{\text{n - factor}}}}$
= $\dfrac{{0.04}}{1}$ (n-factor is 1 for OH-)
So, equivalence of acid = equivalence of base.
equivalence of acid = normality of acid × volume of acid = 0.1 × V
equivalence of base = normality of base × volume of base.
Now, using law of equivalence-
equivalence of acid = equivalence of base
0.1×V=0.04×1
V=0.4 L
=0.4×1000
=400 ml

Hence, the correct option is A

Note- Normality is defined as the number of equivalents of a solute present in one litre of solution. Equivalent is also the term used for amounts of substance like mole with the difference that one equivalent of a substance in different reactions may be different as well as the one equivalent of each substance is also different.
Normality (N) = $\dfrac{{{\text{Number of equivalents of a solute}}}}{{{\text{Volume of solution in litre}}}}$