21.

Methane can be converted into ethane by the reactions

• chlorination followed by the reaction with alcoholic KOH

• chlorination followed by the reaction with aqueous KOH

• chlorination followed by Wurtz reaction

• chlorination followed by decarboxylation

In the reaction, 2FeSO₄ + H₂SO₄ + H₂O₂ → Fe₂(SO₄)₃ + 2H₂O the oxidising agent is

• FeSO₄

• H₂SO₄

• H₂O₂

• methyl cyclopentane

The number of optical isomers of the compound CH₃—CHBr—CHBr—COOH is

• 0

• 1

• 3

• 4

When limestone is heated, CO₂ is given off. The metallurgical operation is

• smelting

• reduction

• calcination

• roasting

Mesa compounds do not show optical activity because

• they do not contain chiral carbon atoms

• they have non-superimposable mirror images

• they contain plane of symmetry

• they do not contain plane of symmetry

Least energetic conformation of cyclohexane is

• chair conformation

• boat conformation

• cis conformation

• E-Z form

An alkyl bromide (X) reacts with sodium in ether to form 4,5-dIethyl octane, the compound X is

• CH₃(CH₂)₃Br

• CH₃(CH₂)₅Br

• CH₃(CH₂)₃CH(Br)CH₃

• CH₃—(CH₂)₂—CH(Br)—CH₂—CH₃

The stability of a lyophobic colloid is due to

• adsorption of covalent molecules on the colloid

• the size of the particles

• the charge on the particles

• Tyndall effect

Which of the following cations will have minimum flocculation value for arsenic sulphide sol?

• Na⁺

• Mg²⁺

• Ca²⁺

• Al³⁺

In face centred cubic lattice, a unit cell is shared equally by how many unit cells?

• 6

• 4

• 2

• 8