Write down the following reaction equations: O2 → H2O → H2 → NH3 → H2O → H3PO4 → H2O → NaOH

1. Obtaining water from simple substances:

O2 + 2H2 = 2H2O.

2. At high temperatures, water decomposes into oxygen and hydrogen:

2H2O = O2 + 2H2.

3. Obtaining ammonia in the reaction of hydrogen and nitrogen:

3H2 + N2 = 2NH3.

4. Without a catalyst, free nitrogen is formed at high temperatures:

4NH3 + 3H3 = 2N2 + 6H2O.

5. Dissolution of phosphorus oxide in water:

3H2O + P2O5 = 2H3PO4.

6. Phosphoric acid, when heated, decomposes into water and pyrophosphate acid:

2H3PO4 = H4P2O7 + H2O.

7. Sodium chloride electrolysis:

2H2O + 2NaCl = 2NaOH + H2 + Cl2.