Question

If x gram weight \[{{H}_{2}}S{{O}_{4}}\] of is present in 1200 mL of a solution of 0.2N strength, then the value of 100x is:
A.1176
B.1200
C.1125
D.None of these

Answer 1

Hint: Equivalent weight is defined as the mass of one equivalent which is the mass of a given substance which will combine with or displace a particular fixed quantity of another substance. The equivalent weight of an element can be defined in the terms of the mass which combines with or displaces 1.008 gram of hydrogen or 8.0 grams of oxygen or 35.5 grams of chlorine. So, in this question we see that it supplies two moles of hydrogen ions per mole of sulphuric acid, so its equivalent weight will be molar mass divided by 2. And this equivalent weight is used in normality. We can keep the following formula in mind to solve this question,
N=\[\dfrac{{{W}_{2}}\times 1000}{E{{w}_{2}}\times V(mL)}\]

Complete step by step answer:
Molar mass of \[{{H}_{2}}S{{O}_{4}}\]​=2×1+32+16×4=98 g/mol

Equivalent weight =\[\dfrac{98}{2}\]​=49g

N=\[\dfrac{{{W}_{2}}\times 1000}{E{{w}_{2}}\times V(mL)}\]
Where, N is normality of the solution, V is the volume of solution, \[E{{w}_{2}}\] is the equivalent weight and \[{{W}_{2}}\] is the given weight.
0.2 = \[\dfrac{{{W}_{2}}\times 1000}{49\times 1200(mL)}\]
⇒\[{{W}_{2}}\]​=11.76 g
Hence, the value of 100x is 1176 which is option A.


Note:
Normality which is also known as the equivalent concentration of a solution is defined as a measure of concentration equal to the gram equivalent weight per litre of solution. Gram equivalent weight is the measure of the reactive capacity of a molecule. The role of the solute in the reaction determines the normality of the solution. Normality is usually used in place of molarity because often 1 mole of acid does not neutralize 1 mole of base.