Which is the best reagent to distinguish between propene and propyne ?

• ammonical AgNO₃

• $\frac{{\mathrm{Br}}_2}{{\mathrm{CCl}}_4}$

• alkaline KMnO₄

• aqueous Br₂

72.

The octane number of a sample of petrol is 40 .It means that its knocking property is equal to the mixture of :

• 40% n-heptane + 60% iso-octane

• 40% petrol + 60% iso-octane

• 60% n-heptane + 40% iso-octane

• 60% petrol + 40% iso-octane

The main component of marshgas is :

• methane

• ethane

• butane

• isobutane

Assertion: The presence ofnitro group facilitates nucleophilic substitution reactions in aryl halides.

Reason: The intermediate carbanion is stabilised due to the presence of nitro group.

• If both assertion and reason are true and reason is the correct explanation of the assertion.

• If both assertion and reason are true but reason is not the correct explanation of the assertion.

• If assertion is true, but reason is false.

• Both assertion and reason are false statements.

Assertion : Addition of HBr on 2-butene gives two isomeric products.

Reason: Addition of HBr on 2-butene follows Markovnikov's rule.

• If both assertion and reason are true and reason is the correct explanation of the assertion.

• If both assertion and reason are true but reason is not the correct explanation of the assertion.

• If assertion is true, but reason is false.

• Both assertion and reason are false statements.

Assertion : p-O₂N- C₆H₅COCH₃ is prepared by Friedel Crafts acylation of nitrobenzcne.

Reason : Nitrobenzene easily undergoes electrophilic substitution reaction.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : Alkyl isocyanides in acidified water give alkyl formamides.

Reason : In isocyanides, carbon first acts as a nucleophile and then as an electrophile.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion : Cyclopentadienyl anion is much more stable than allyl anion.

Reason : Cyclopentadienyl anion is aromatic in character.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Action of acetylene on dilute H₂SO₄ gives :

• acetic acid

• acetaldehyde

• acetone

• acetoacetic ester

The treatment of benzene with isobutene in the presence of sulphuric acid gives

• iso -butyl benzene

• tert -butyl benzene

• n -butyl benzene

• no reaction