Final answer:
The molecular formula for a molecule made by linking three glucose molecules by dehydration reactions is C₁₈H₃₂O₁₆. The process of linking the molecules involves losing two water molecules, which is accounted for in the final formula.
Step-by-step explanation:
The question pertains to the molecular formula of a carbohydrate formed by dehydration reactions linking three glucose molecules. Each glucose molecule has the molecular formula C₆H₁₂O₆. When glucose molecules are combined in a dehydration synthesis reaction, they lose a water molecule (H₂O) for each bond formed. Since two bonds are formed when three glucose molecules combine, the total loss will be two water molecules (2 H₂O = H₄O₂). Therefore, we subtract the elements of two water molecules from the combined total of the three glucose molecules.
To calculate the new molecular formula, it would be: (C₆H₁₂O₆)ₓ3 - H₄O₂ = C₁₈H₃₆O₁₈ - H₄O₂ = C₁₈H₃₂O₁₆. Thus, the correct molecular formula for a molecule made by linking three glucose molecules by dehydration reactions is C₁₈H₃₂O₁₆, which corresponds to option E) C₁₈H₃₂O₁₆.