Organic Chemistry MCQ with Answers

Organic Chemistry MCQ with Answers

76) A fuel has the same knocking property as a mixture of 70% isooctane (2,2,4−trimethylpentane) and 30% n−heptane by volume. The octane number of the fuel is:

Answer is:

70

77) To a mixture of conc. HNO₃ and conc. H₂SO₄, benzene was added. This mixture was heated for 30 minutes at 100^oC. The main product is:

Answer is:

m−dinitrobenzene

78) An unknown compound A has the formula C₄H₆. When A is treated with excess of Br₂, a new compound B is formed with formula C₄H₆Br₄. A also gives white ppt. with Tollen′s reagent. The compound A may be:

Answer is:

But−1−yne

Explanation:

The data suggests that compound A is a terminal alkyne.

79) In the presence of peroxide, hydrogen chloride and hydrogen iodide do not give anti Markownikov′s addition to alkenes because:

Answer is:

One of the steps is endothermic in both the cases

80) Xylene on treatment with Br₂⁄FeBr₃ gives only one product. Xylene was:

Answer is:

p−xylene

Explanation:

In p−xylene, all the positions are equivalent and give only one monosubstituted product.

13
14
15
16
17
18
19