Question

In which of the following cases, is the empirical formula same as the molecular formula?

• A. C₁₂H₂₂O₁₁
• B. C₆H₆
• C. C₃H₅COOH
• D. C₆H₁₂O₆

Answer 1

The correct option is A

C₁₂H₂₂O₁₁

The explanation for the correct option:

The empirical formula is the simplest formula of the compound which gives the simplest whole-number ratio of the atoms of the various elements present in one molecule of the compound. Example: Molecular formula of glucose is C₆H₁₂O₆ but the simplest whole-number ratio of atoms in glucose is CH₂O. Therefore, CH₂O is the empirical formula.

The molecular formula is the actual formula of the compound which gives the actual number of atoms present in the molecule of the compound. For example, the molecular formula of glucose is C₆H₁₂O₆.

• If the simplest whole-number ratio of the atoms of the various elements can be attained from its molecular formula, then it has an empirical formula.
• If the simplest whole-number ratio of the atoms of the various elements cannot be attained from its molecular formula, then it does not have an empirical formula.

The formula of sucrose (C₁₂H₂₂O₁₁) can not be simplified further, therefore its empirical and molecular formula is the same.

The explanation for the incorrect options:

C₆H₆ can be further simplified into CH

C₃H₅COOH or (C₄H₆O₂) can be further simplified into C₂H₃O

C₆H₁₂O₆ can be further simplified into CH₂O

Hence option (a) is correct.