Question

Nitration mixture is known as:
A.Mixture of fuming nitric acid and diluted sulphuric acid.
B.Mixture of fuming nitric acid and concentrated sulphuric acid.
C.Mixture of fuming nitric acid and diluted hydrochloric acid.
D.Mixture of fuming nitric acid and diluted sodium chloride

Answer 1

Hint: To answer this question, we must recall what nitration mixture is, what its properties are and how is it utilized. We should know that nitration mixtures generally constitute nitric acid and sulphuric acid.

Complete step by step answer:
-It is imperative to know that nitration mixtures are used in the nitration of organic substances for example aromatic compounds. This mixture is colorless but is often found to be a yellow-reddish liquid, sometimes with fuming reddish brown vapors by virtue of nitrogen dioxide. It is soluble in water and the dissolution releases large amounts of heat proving that it is highly exothermic.
-Nitrating mixture is prepared in the laboratory by cooling a volume of concentrated sulfuric acid, usually in an ice bath. An equal volume of concentrated nitric acid is then slowly added to it keeping the solution at constant temperature. Also called mixed acid, this mixture is highly corrosive and is a major fire hazard. It is unstable, and should be produced and stored with extreme care.
-The mixture contains concentrated nitric acid and sulfuric acid, in a 1:1 ratio.

Hence, the correct answer is Option (B) Mixture of fuming nitric acid and concentrated sulphuric acid.

Note: We should note that concentrated nitric acid also forms a nitrating mixture with certain inorganic compounds like aluminium chloride and boron fluoride in addition to sulphuric acid. All these generate the nitronium cation which is essential in nitration reactions.