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Electrolysis of potassium maleate yields Ethyne.

(i) Barbeque is usually done in the open. In cold countries, although both propane and butane can be used but propane is preferred because it works better in low temperature. The reason being that due to lower boiling point (i.e., 231 K), propane always remains as a gas in the cylinder inspite of cooling produced by Joule Thomson effect during its use and thus ensures a constant supply of the gas. In contrast, butane due to its higher boiling point (272.5 K) and cooling produced by Joule - Thomson effect, it becomes a liquid in the cylinder and thus the supply of the gas becomes slower and slower as the gas is being used. 

(ii) Butane is used in cigarette lighters since it can be easily liquefied at room temperature. 

(iii) Mineral oil is a mixture of liquid alkanes containing 16-18 carbon atoms and is used as a laxative and as a lubricant. 

(iv) Alkanes with 18 or more carbon atoms are waxy solids. These are used as waxy coatings on fruits and vegetables to help them retain moisture, inhibit mould growth and enhance appearance. 

(v) Vaseline or petroleum jelly, is a mixture of solid alkanes having low melting points. It can prevent moisture loss and chapped lips and soften nail cuticles. It is also used in ointments and cosmetics.

Correct answer is (a) C₈H₁₈ 

Three molecules of acetylene undergoes polymerisation to give benzene.

(a) Formaldehyde

(a) Pent – 1 – ene

When a solution of haloalkanc in dry ether is treated with sodium metal, higher alkanes are produced. This reaction is known as Wurtz reaction. 

For example:

CH₃-Br (Methyl bromide) + 2Na + Br- CH₃ \(\overset {dry ether} {\longrightarrow}\) CH₃ - CH₃ (ether) + 2NaBr

(d) 2, 2, 3, 3 tetra chiorobutane

Sodalime is the mixture of NaOH + CaO.

3-Ethyl, 2-methylpentane

The phenomenon in which the same molecular formula may exhibit different structural arrangement is called isomerism. 

There are two types of isomerism. namely. 

• Structural isomerism 
• Stereoisomerism

Methane gas is also called as Marsh gas.

• Methane is the major component of the atmosphere of jupiter, Saturn, Uranus and Neptune but only minor component of earth atmosphere. 
• Decomposition of plant and animal matter in an oxygen deficient environment like swamps, marshes bogs and the sediments of lakes produces methane gas. It is otherwise known as marsh gas.

• Frozen mixture of water and methane gas is chemically known as methane clathrate. 
• The methane molecule which is produced by biological process under the deep -ocean (at 4°C and 50 atm) does not simply reach the surface instead each molecule is trapped inside the clusters of 6 to 18 water molecules forming methane clathratcs.

(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).

Correct answer is (a) – NH₂ 

(c) configurational isomers

(iii) and (iv). In structures (i) and (ii), two identical groups are attached to one of the doubly bonded carbon atom.

Compound (c) will exhibit geometrical isomerism.

Correct answer is (d) slower

b) 2,3-dimethyl-2-butene

Pentane having a continuous chain of five carbon atoms has the highest boiling point (309.1K) whereas 2,2 – dimethylpropane boils at 282.5K. With increase in number of branched chains, the molecule attains the shape of a sphere. This results in smaller area of contact and therefore weak intermolecular forces between spherical molecules, which are overcome at relatively lower temperatures.

(iii) CH₄ + O₂ → C(s) + 2H₂O (l)

(b&c)

b) trans-pent-2-ene c) cis-Hex-3-ene

c) HI> HBr> HCl