WAEC Chemistry 2019 Paper

Concept:The empirical formula of a compound shows the simplest whole-number ratio of atoms of each element present in it.Explanation:Since the percentages sum to $100\%$, assume a $100$ g sample of the compound.In this sample: mass of C $= 72$ g, mass of H $= 12$ g, mass of O $= 16$ g.Convert each mass to moles by dividing by the atomic mass of the element.Moles of C $= \frac{72}{12} = 6$ molMoles of H $= \frac{12}{1} = 12$ molMoles of O $= \frac{16}{16} = 1$ molThe mole ratio is C : H : O $= 6 : 12 : 1$.This ratio is already in its simplest whole-number form, so the empirical formula is $\mathrm{C_6H_{12}O}$.Answer:The empirical formula is $\mathrm{C_6H_{12}O}$.Therefore, the correct option is B.