Select the correct answer - The organic compound, which gives a red precipitate with ammoniacal cuprous chloride and undergoes an addition reaction –

A: Ethane
B: Ethene
C: Ethyne
D: Ethanol

Compound 'X' is bubbled through bromine dissolved in CCl₄ and the product formed is CH₂Br – CH₂Br.

i) Draw the structural formula of 'X' and state what type of reaction 'X' has undergone.

(ii) State your observation for the above reaction.

(iii) Name the compound formed when steam reacts with 'X' in the presence of an acid, eg. phosphoric acid.

(iv) What is the procedure for converting the product formed in (iii) above, back to 'X' ?

Select the correct answer - The organic compound which when mixed with ethyl alcohol, [ethanol], makes it spurious.

A: Methanol
B: Methanoic acid
C: Methanal
D: Ethanoic acid

Name a gaseous hydrocarbon commonly used for welding purposes.