Hydrocarbons

Treatment of buta-1,3-diyne with NaNH2 (2 equivalents), followed by reaction with excess of trans- CH3-CH=CH-CH2-Br gives X as the major product. The maximum number of carbon atoms that are collinear (in a straight line) in X is .

In the following reaction sequence, the major product Q is L-Glucose [ii) Cr2O3, 775 K, 10-20 atm]i) HI, P [UV]Cl2 (excess) Q

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Which of the following are aromatic?

1. Benzene
2. Cyclopentadienyl anion
3. Cyclooctatetraene
4. Tropylium cation