571.

The electrophile involved in the nitration of benzene is :

• NO₂

• NO₂⁺

• NO

• NO₂^-

Which of the following gives propyne on hydrolysis?

• Al₄C₃

• Mg₂C₃

• B₄C

• La₄C₃

What is obtained , when propene is treated with N-bromo succinimide ?

• CH₃-CBr=CH₂

• BrCH₂-CH=CH₂

• BrCH₂-CH=CHBr

• BrCH₂-CHBr-CH₂Br

Poisonous gas 'Lewisite' is obtained by the reaction of :

• CH$\equiv$CH and AsCl₃

• CH₂=CH₂ and AsCl₃

• CH$\equiv$CH and S₂Cl₂

• CH₂=CH₂ and NOCl

Assertion : [Co(NO₂)₃(NH₃)₃] does not show optical isomerism.

Reason : It has a plane of symmetry.

• 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.

What will be the main product, when benzene vapours are passed over V₂O₅ at 450°C ?

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

• ammonical AgNO₃

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

• alkaline KMnO₄

• aqueous Br₂

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.