Question

3.7g of calcium hydroxide is present in 100 ml of solution. The normality of the solution is
A. 1N
B. 2N
C. 0.25 N
D. 0.5 N

Answer 1

Hint :A gram equivalent weight of solute per litre of solution is the normality unit of concentration for a chemical solution. To indicate concentration, a specific equivalency factor must be employed. N is a common unit of normalcy. The number of equivalents per litre of solution is the definition of normality.

Complete Step By Step Answer:
In chemistry, normality is one of the terms used to describe the concentration of a solution. It is sometimes referred to as the equivalent concentration of a solution and is abbreviated as ‘N.' It is mostly used to determine the amount of reactive species in a solution, as well as during titration reactions and circumstances requiring acid-base chemistry. Normality is defined as the number of grams or mole equivalents of solute contained in one litre of a solution, according to the standard definition. The amount of moles of reactive units in a chemical is what we mean when we say equivalent
Molecular mass of $Ca{(OH)_2}$is 40 + 17 + 17 = 74 g
${\text{Number of moles = }}\dfrac{{{\text{Given}}\,{\text{mass}}}}{{{\text{Molecular mass}}}}$
${\text{Number of moles = }}\dfrac{{{\text{Given}}\,{\text{mass}}}}{{{\text{Molecular mass}}}} = \dfrac{{3.7}}{{74}} = \dfrac{1}{{20}}moles$
The molar concentration divided by an equivalency factor yields the equivalent concentration or normalcy of a solution in chemistry:
\[Normality{\text{ }} = \;N = \dfrac{{Eq}}{V}\]
Now the equivalence factor is 2
Volume = 100 ml = 0.1 l
Upon substituting
\[Normality{\text{ }} = \dfrac{{Eq}}{V} = \dfrac{{1 \times 2}}{{20 \times 0.1}} = 1\]
\[ \Rightarrow {\text{Normality = 1N}}\]
Hence option D is correct.

Note :
Gathering information regarding the equivalent weight of the reactive substance or the solute is the first tip that students may use. To understand about the molecular weight and valence, consult a textbook or reference book. The number of gram equivalents of the solute is calculated in the second phase. It is important for students to remember that the volume is measured in litres.