To determine the structures of X, Y, and Z, let's analyze the given information:
- Hydrocarbon X, C4H6 (0.50g), was shaken with hydrogen and palladium until uptake of H2 ceased; 415cm³ of H2 were absorbed.
From this information, we can infer that hydrocarbon X has undergone hydrogenation, where it reacts with hydrogen (H2) in the presence of a palladium catalyst. The amount of hydrogen gas absorbed, 415 cm³, is a measure of the stoichiometry of the reaction.
The molar volume of hydrogen gas at standard temperature and pressure (STP) is approximately 22.4 L/mol. By converting the given volume of 415 cm³ to liters and using the molar volume, we can determine the number of moles of hydrogen gas absorbed:
415 cm³ * (1 L / 1000 cm³) * (1 mol / 22.4 L) = 0.0185 mol
Since hydrogenation typically involves the addition of two hydrogen atoms per double bond, we divide the number of moles of hydrogen gas absorbed by 2:
0.0185 mol / 2 = 0.00925 mol
Therefore, hydrocarbon X must have had 0.00925 mol of double bonds. Given that the molar mass of X is 0.50 g, we can calculate its molar mass:
Molar mass of X = (0.50 g) / (0.00925 mol) = 54.05 g/mol
The closest empirical formula to C4H6 with a molar mass close to 54.05 g/mol is C8H12. Therefore, X is likely to be cyclooctene (C8H12).
- Reaction with HgSO4 in dil. H2SO4 yielded Y, CH3O.
The reaction with HgSO4 in dilute H2SO4 suggests that hydrocarbon X (cyclooctene) is an alkene and can undergo an addition reaction. The product, Y, is stated to be CH3O.
Based on this information, Y is likely to be methoxyethane, also known as methyl ethyl ether (CH3OCH2CH3).
- Polymerisation of X gave Z, C12H8.
Polymerization of cyclooctene (X) results in a compound with a higher molecular weight. The product, Z, has the molecular formula C12H8.
From this information, Z is likely to be naphthalene. Naphthalene consists of two benzene rings fused together, forming a polycyclic aromatic hydrocarbon.
In summary, based on the given information:
X is likely to be cyclooctene (C8H12). Y is methoxyethane or methyl ethyl ether (CH3OCH2CH3). Z is naphthalene (C12H8).