Question

What is a normal solution?
A.One gram equivalent mass of the substance in one litre solution.
B.One gram molecular mass of the substance in one litre solution.
C.One gram equivalent mass of the substance in mL of the solution.
D.Is that whose concentration is known.

Answer 1

In the above question, we have to choose the most appropriate definition of normality. For this, we have to look after the definition of normality and choose the most appropriate one.

Complete answer:
The concentration of all the solutions is supposed to be expressed either in Molarity(M), Normality(N) and Molality(m). Concentration also depends on the quantities of solutes and solvent. Normality is equal to molar mass of compound divided by its valency.
MOLARITY (M) – Number of moles of the solute present in one litre of the solvent is called molarity.
NORMALITY (N) – Number of gram equivalent weight of the solute present in one litre of the solvent is called normality.
MOLALITY (m) – Number of moles of the solute present in one kg of the solvent is molality.
If we consider,
Option a- 1g of equivalent mass of the substance in 1L of solution. It’s correct because it completely suits the definition of normality.
Option b - contain 1g molecular mass of the substance in 1litre solution. It’s wrong because in normality we won’t measure molecular mass.
Option c – contain 1g equivalent mass of the substance in 100 ml of the solution. It’s wrong because in normality we have to consider 1 litre of the solution not 100 ml.
Option d - whose concentration is known. This is wrong because if we concentrate we cannot say it as normality.

Hence, option A is correct.

Note:
In normality, the equivalent weight may be sound confusing. The equivalent weight is the mass of the one equivalent, that is the mass of a given substance which combines with the mass of fixed quantity of another substance.
For example, for acid-base reaction, the equivalent mass of an acid or a base is the mass which reacts with one mole of hydrogen cation.