(c)
Atom Atomic Percentage $\frac{\mathbf{b}}{\mathbf{a}}\mathbf{= x}$ Ratio
Mass $\mathbf{(a)}$ $\mathbf{(b)}$
C 12 40 $\frac{40}{12} = 3.33$ 1
H 1 6.66 $\frac{6.66}{1} = 6.66$ 2
O 16 53.34 $\frac{53.34}{16} = 3.33$ 1
Hence, empirical formula $= CH_{2}O$