Question

The weight of crystalline Oxalic acid $({H_2}{C_2}{O_4}.{H_2}O)$ required to prepare 100ml of 0.05N solution is
(A) 0.1575g
(B) 1.1575g
(C) 0.315g
(D) 0.27g

Answer 1

Hint: To answer this question, we must focus on the concept of normality and how to calculate it. Normality can be described as the number of gram or mole equivalents of solute present in one liter of a solution.

Complete step by step solution:
Oxalic acid is an essential household chemical that is used, like many acids, as a cleaner for various things.
We already know that the basicity of Oxalic acid = n factor = 2
Given, Normality of Oxalic acid = 0.05N, Volume = 100ml = 0.1L
Therefore, we can now calculate the Molarity of Oxalic acid from the formula:
$Molarity = \dfrac{{Normality}}{{n - factor}}$
$\dfrac{{0.05}}{2}M = 0.025M$
We can calculate the number of moles of acid present in solution.
$No.\,of\,moles\, = \,Molarity\, \times \,Volume$
On substituting we get,
$0.025 \times 0.1\,mole\, = 2.5 \times {10^{ - 3}}moles$
We know that the Molecular weight of Oxalic acid = 108g/mol
Therefore, Mass of Oxalic acid in solution = no. of moles x Molecular weight
$2.5 \times {10^{ - 3}} \times 108g\, = \,0.27g$
Hence, the correct answer is Option (D) 0.27g

Additional information:
Normality is sometimes used in place of molarity because often 1 mole of acid does not completely neutralize 1 mole of base. Hence, in order to have a one-to-one relationship between acids and bases, many chemists prefer to express the concentration of acids and bases in normality.

Note: The normal concentration of a solution or normality is always equal to or greater than the molar concentration or molarity of a solution. The normal concentration can be calculated by multiplying the molar concentration by the number of equivalents per mole of solute.