Question

Number of gram equivalent of solute in $100\,\,mL$ of $5N$ $HCl$ solution is:
(A) $50$
(B) $50$
(C) $5$
(D) $0.5$

Answer 1

The normality of the $100\,\,mL$ solution of the hydrochloric acid ( $HCl$ ) is given . But note that the volume of the ( $HCl$ ) is not given in the SI unit. Convert it in the SI unit (i.e. litre ) by dividing it by $1000$ and then use the relation between the Normality and gram equivalent’s formula to obtain the number of gram equivalent. And then finally, we can conclude the correct answer.

Complete step-by-step solution: Step 1: In this step we will enlist all the given quantities.
Normality of $HCl$ solution = 5 N
Volume of the solution = $100\,\,mL$
Step 2: In this step we will convert the volume into SI unit, i.e. from milliliter to liter,
Volume of the solution $= {\text{ }}100{\text{ }}mL{\text{ }} = {\text{ }}0.1{\text{ }}L\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\left( {1{\text{ }}L{\text{ }} = {\text{ }}1000{\text{ }}mL} \right)$
Step 3: In this step we will use the relation between the normality and gram equivalent’s formula to obtain the number of gram equivalents:
The relation is given by:
Number of gram equivalents $= \,\,Normality\,\, \times \,\,Volume\,(in\,\,L)$
Number of gram equivalents of $HCl$ $= \,5 \times 0.1\,\, = \,\,0.5\,\,grams$ equivalents per liter.

So clearly, we can conclude the correct answer is Option D.

Note: The normality of a solution is the gram equivalent weight of a solute per liter of solution. It may also be called the equivalent concentration. For example, the concentration of a hydrochloric acid solution might be expressed as $0.1N$ $HCl$ . A gram equivalent weight or equivalent is a measure of the reactive capacity of a given chemical species (ion, molecule, etc.). The equivalent value is determined using the molecular weight and valence of the chemical species.