The molecular formulas of methane, ethane and butane are CH4, C2H6 and C4H10, respectively. What would be their empirical formulas respectively? A. CH4, CH3 and C2H5 B. CH4, C6H6 and C2H2 C. CH4, C2H6 and C4H10 D. C4H, 2CH3 and 2C2H5

The correct answer is: A. CH4, CH3 and C2H5

The empirical formula of a compound is the simplest whole-number ratio of the atoms of each element in the compound. To find the empirical formula, you divide the subscripts of each element in the molecular formula by the greatest common factor of those subscripts.

For methane, the molecular formula is CH4. The greatest common factor of 1 and 4 is 1, so the empirical formula is CH4.

For ethane, the molecular formula is C2H6. The greatest common factor of 2 and 6 is 2, so the empirical formula is CH3.

For butane, the molecular formula is C4H10. The greatest common factor of 4 and 10 is 2, so the empirical formula is C2H5.

Option B is incorrect because the empirical formula of ethane is CH3, not C6H6. Option C is incorrect because the empirical formula of butane is C2H5, not C4H10. Option D is incorrect because the empirical formulas of methane, ethane, and butane are not C4H, 2CH3, and 2C2H5, respectively.