Consider the following compounds ____________ (i) \(CH _{3} CH _{2} C \left( CH _{3}\right)_{2} CH _{2} CH _{3}\) (ii) \(CH _{3} CH _{2} CH _{2} CH _{3}\) (iii) \(CH _{3} CH \left( CH _{3}\right) C \left( CH _{3}\right)_{2} CH _{3}\) (iv) \(CH _{3} CH \left( CH _{3}\right) CH _{3}\). The correct arrangement of the compounds in their increasing order of volatility is
A. iv, ii, i, iii B. iii, i, ii, iv C. ii, i, iii, iv D. iii, i, iv, ii
Correct Answer: B
Explanation
Volatility decreases (boiling increases) as the inter - molecular forces in compounds become stronger and vice - versa. For a group of isomeric compounds, volatility increases (or boiling point decreases) as the degree of branching of carbon chain increases. Down the homologous series (as carbon number increases) volatility decreases (boiling point increases) in spite of branching. (i) and (iii) have 7 carbon atoms and so will have lower volatility than (ii) and (iv) with 4 carbon atoms. None of the options is correct
