Derive the formula of the substance according to the following data: H-1.25% P-38.75% O-60%

Knowing the molar masses of these elements, we find their mass ratios in an unknown compound:
m (H) = W (H) / Mr (H) = 1.25% / 1 = 1.25.
m (P) = W (P) / Mr (P) = 38.75% / 31 = 1.25.
m (O) = W (O) / Mr (O) = 60% / 16 = 3.75.
To get integers, divide the resulting values by the minimum – 1.25:
We get H: P: O = 1: 1: 3.

Which corresponds to the formula of the compound HPO3 – metaphosphoric acid.