The compound has a composition: w (As) -65.22%, w (O) -34.78%. Find its formula and make up the reaction of interaction

The compound has a composition: w (As) -65.22%, w (O) -34.78%. Find its formula and make up the reaction of interaction with water, taking into account that the process proceeds in the same way as phosphorus (5) oxide reacts with water.

To solve the problem, let’s write down the data by condition:
1. Given: AsxOy – inorganic compound, oxide.
W (As) = 65.22%
W (O) = 34.78%
Determine: molecular formula.
2. Find the number of moles of arsenic, oxygen:
Y (As) = m / M = 65.22 / 74.9 = 0.8;
Y (O) = m / M = 34.78 / 16 = 2.17
3. Ratio:
X: Y = 0.8: 2.17 = 1: 2.7 = 1: 3.
Molecular Formula: As2O3
As2O3 + 5H2O = 2H2 + 2H3AsO4 – the reaction with water leads to the formation of orthoarsenous acid.
Answer: As2O3 is arsenic oxide.