"Published in Suisun City, California, USA"
In order to carry out nitration reaction, it is desired to have a mixed acid containing 39% HNO3, 42% H2SO4, and 19% H2O by weight. Nitric acid of 68.3% by weight is readily available. Calculate the
(a) required strength of sulfuric acid in order to obtain the above mixed acid and
(b) the weight ratio of nitric acid to sulfuric acid to be mixed.
Solution:
The given word problem is about the mixing of different acids which involves the principles of Stoichiometry. The concentration or strength of concentrated sulfuric acid is unknown and we need to solve it. The total amount of a substance in the reactants or incoming ingredients must be equal to the total amount of a substance in the final products. In short, the Law of Conservation of Mass must be followed all the time. Since all incoming substances are acids, then there's no chemical reactions involved in the mixture. To illustrate the given problem, it is better to draw the flow diagram as follows
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| Photo by Math Principles in Everyday Life |
Since the amount of concentrated nitric acid, concentrated sulfuric acid, and mixed acids are not given in the problem, let's assign a basis of 100 kg of mixed acid in the problem.
Basis: 100 kg of Mixed Acids
Let x = be the amount of Concentrated Nitric Acid
y = be the amount of Concentrated Sulfuric Acid
Overall Material Balance of Mixer:
Material Balance of Nitric Acid:
Substitute the value of x to the above equation, we have
Material Balance of Sulfuric Acid:
Therefore, the concentration or strength of Concentrated H2SO4 is
The weight ratio of Concentrated HNO3 to Concentrated H2SO4 is
