How do you balance phosphoric trichloride reacts with water to form phosphoric acid and hydrochloric acid?

Answer 1

Therte is no straight answer on this question.

From PCl3 (trichloride) only phosphorous acid, H3PO3, can be obtained (oxidation state of Phophor is +3 and must stay unchanged due to lack of an oxidator)

1. PCl3 + H2O --> H3PO3 + HCl

   Balance O:

2. PCl3 + 3H2O --> H3PO3 + HCl

   Balance Cl

3. PCl3 + 3H2O --> H3PO3 + 3HCl

   Check H

4. 3*2 = 3+3 => OK!

Phosphoric acid, H3PO4, can only be obtained from PCl5 (pentachloride) (The oxidation state of Phophor must have been +5 and could not be changed due to lack of a reductant)

1. PCl5 + H2O --> H3PO4 + HCl

   Balance O:

2. PCl5 + 4H2O --> H3PO4 + HCl

   Balance Cl

3. PCl5 + 4H2O --> H3PO4 + 5HCl

   Check H

4. 4*2 = 3+5 => OK!