Ascorbic acid has a molar mass of 176.14 g/mol. What is the molecular formula of ascorbic acid?
The correct answer and explanation is :
Molecular Formula of Ascorbic Acid: C₆H₈O₆
Ascorbic acid, commonly known as Vitamin C, has a molar mass of 176.14 g/mol. Its molecular formula is C₆H₈O₆, which means each molecule consists of 6 carbon atoms, 8 hydrogen atoms, and 6 oxygen atoms.
Explanation (Approx. 300 Words):
To determine the molecular formula of a compound, we must know both its empirical formula and its molar mass. The empirical formula represents the simplest whole-number ratio of atoms in a compound, while the molecular formula shows the actual number of each type of atom in a molecule.
In the case of ascorbic acid, chemists have analyzed the substance through various methods, such as elemental analysis and mass spectrometry, and found that it is composed of carbon (C), hydrogen (H), and oxygen (O).
From combustion analysis and experimental data, the empirical formula of ascorbic acid is determined to be C₃H₄O₃. This empirical unit has a molar mass of:
- C (12.01 g/mol) × 3 = 36.03 g/mol
- H (1.008 g/mol) × 4 = 4.032 g/mol
- O (16.00 g/mol) × 3 = 48.00 g/mol
- Total = 88.06 g/mol
Now, to find the molecular formula, we compare the actual molar mass to the empirical molar mass: Molar mass of ascorbic acid÷Empirical formula mass=176.14÷88.06≈2\text{Molar mass of ascorbic acid} ÷ \text{Empirical formula mass} = 176.14 ÷ 88.06 ≈ 2
This means the molecular formula contains two empirical units, so we multiply each subscript in the empirical formula by 2: (C3H4O3)×2=C6H8O6(C₃H₄O₃) × 2 = C₆H₈O₆
Thus, the molecular formula is C₆H₈O₆.
This formula not only matches the compound’s molar mass but also aligns with its known structure and biological function. Ascorbic acid is a crucial antioxidant and plays a key role in collagen synthesis and immune function. Its specific arrangement of atoms allows it to donate electrons and neutralize free radicals in the body.
