21.

Which of the following gives propyne on hydrolysis?

• Al₄C₃

• Mg₂C₃

• B₄C

• La₄C₃

The pair of amphoteric hydroxides is

• Al(OH)₃, LiOH

• Be(OH)₂, Mg(OH)₂

• B(OH)₃, Be(OH)₂

• Be(OH)₂, Zn(OH)₂

Which of the following is a carbonate ore?

• Pyrolusite

• Malachite

• Diaspore

• Cassiterite

Which of the following chemicals are used to manufacture methyl isocyanate that caused "Bhopal Tragedy"?

(i) methylamine 

(ii) phosgene

(iii) phosphine

(iv) dimethylamine

• (i) and (iii)

• (iii) and (iv)

• (i) and (ii)

• (ii) and (iv)

Which of the following molecules is most suitable to disperse benzene in water?

Among the following the strongest nucleophile is

• C₂H₅SH

• CH₃COO^-

• CH₃NH₂

• NCCH₂^-

Among the following the most stable compound is

• cis-1,2-cyclohexanediol

• trans-1,2-cyclohexanediol

• cis-1,3-cyclohexanadiol

• trans-1,3-cyclohexanediol.

3-Phenylpropene on reaction with HBr gives (as a major product)

• C₆H₅CH₂(Br)CH₃

• C₆H₅CH(Br)CH₂CH₃

• C₆H₅CH₂CH₂CH₂Br

• C₆H₅CH(Br)CH=CH₂

Assertion : Borax bead test is not suitable for Al(III).

Reason : Al₂O₃ is insoluble in water.

• 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 : Ozone is a powerful oxidising agent in comparison to O₂.

Reason : Ozone is diamagnetic but O₂ is paramagnetic.

• 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.