Ethanol reacts with sodium and forms two products. These are:

Which among the following are unsaturated hydrocarbons?

(i) H₃C — CH₂ — CH₂ — CH₃

(ii) H₃C — C ≡ C — CH₃

(iii)

(iv)

Pentane has the molecular formula C₅H₁₂. It has:

Vinegar is a solution of:

Which of the following does not belong to the same homologous series?