Which of the following molecular formulas is also an empirical formula?

• A. C_4H_{10}
• B. C_6H_{12}O_6
• C. CH_2O
• D. C_2H_4

Answer: (C)

Verified step by step guidance

1. Understand the difference between a molecular formula and an empirical formula. A molecular formula shows the actual number of atoms of each element in a molecule, while an empirical formula shows the simplest whole-number ratio of atoms in the compound.
2. Look at each given formula and determine if it can be simplified to a smaller whole-number ratio. For example, check if the subscripts in the formula can be divided by a common factor.
3. For C_4H_{10}, divide both subscripts by their greatest common divisor (GCD). The GCD of 4 and 10 is 2, so dividing gives C_2H_5, which is simpler than the original formula, so C_4H_{10} is not an empirical formula.
4. For C_6H_{12}O_6, divide all subscripts by their GCD, which is 6. This gives CH_2O, which is a simpler ratio, so C_6H_{12}O_6 is not an empirical formula, but CH_2O is.
5. For C_2H_4, divide both subscripts by their GCD, which is 2, resulting in CH_2. Since CH_2 is simpler, C_2H_4 is not an empirical formula. Therefore, the formula CH_2O is already in its simplest form and is an empirical formula.