A monocyclic aromatic hydrocarbon (one benzene ring bearing only saturated alkyl substituents) has the general formula C_nH_2n-6 and a molar mass of 134 g/mol (C = 12, H = 1). How many carbon atoms does one molecule contain?

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A monocyclic aromatic hydrocarbon (one benzene ring bearing only saturated alkyl substituents) has the general formula $C X_{n} H X_{2 n - 6}$ and a molar mass of 134 g/mol (C = 12, H = 1). How many carbon atoms does one molecule contain?

Answer: D

The molar mass is 12n + (2n - 6) = 14n - 6. Setting 14n - 6 = 134 gives 14n = 140 and n = 10. The formula is C10H14 (for example butylbenzene), and its DU = (20 + 2 - 14)/2 = 4, as expected for a benzene ring.

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A monocyclic aromatic hydrocarbon (one benzene ring bearing only saturated alkyl substituents) has the general formula CXn​HX2n−6​​ and a molar mass of 134 g/mol (C = 12, H = 1). How many carbon atoms does one molecule contain?

Answer: D

More questions on Classification and degree of unsaturation

A monocyclic aromatic hydrocarbon (one benzene ring bearing only saturated alkyl substituents) has the general formula $C X_{n} H X_{2 n - 6}$ and a molar mass of 134 g/mol (C = 12, H = 1). How many carbon atoms does one molecule contain?