Carbohydrates can generally be represented by the general formula C$_x$(H$_2$O)$_y$, for fructose the value for "X" is

Analyze the question: Carbohydrates fit the general formula Cₓ(H₂O)ᵧ. We need the value of x for fructose.

Concept: Fructose is a monosaccharide (a ketohexose) with the molecular formula C₆H₁₂O₆. It is an isomer of glucose.

Solution:

1. Write the molecular formula of fructose: C₆H₁₂O₆
2. Rewrite it in the form Cₓ(H₂O)ᵧ: • Carbon atoms: 6, so x = 6 • Hydrogen atoms: 12 = 2y, so y = 6 • Oxygen atoms: 6 = y, so y = 6 (consistent)
3. So fructose = C₆(H₂O)₆, giving x = 6.

Checking the options:

• A (3): This would fit a triose such as glyceraldehyde, C₃(H₂O)₃.
• B (12): This is the number of hydrogen atoms in fructose, and it is also the carbon count in sucrose, C₁₂(H₂O)₁₁. It is not the carbon count in fructose.
• C (5): This would fit a pentose such as ribose, C₅(H₂O)₅.
• D (6): This fits hexoses such as fructose and glucose. ✔

Tip: The prefix tells you the carbon count: tri- = 3, pent- = 5, hex- = 6. Glucose, fructose and galactose are all hexoses, so they all have C₆H₁₂O₆. Disaccharides like sucrose are C₁₂H₂₂O₁₁, because they lose one H₂O when two monosaccharides join.