Hydrochloric acid hcl is added to bleaching powder
Answers
what to do in the question
Answer:
Assuming you want to know what the reaction is:
4HCl + Ca(ClO)2 = CaCl2 + 2Cl2 + 2H2O
Explanation:
At first Ca(ClO)2, also known as bleaching powder, will dissolve and Ca(2+) ions and ClO- ions will be in solution.
HCl, being a strong acid, will protonate the ClO- anion in solution. The reaction is:
HCl + ClO- = HClO + Cl-
The following equilibrium:
HCl(aq) + HClO(aq) = Cl2(g) + H2O(l)
is going to consume the HClO (= hypochlorous acid). Note that I wrote the states of matter, espacially the fact that chlorine is gaseous. The chlorine gas is going to bubble out of the solution, driving the reaction to completion.
If you know how to add up reactions then this is the end of my explanation, if not then continue reading:
We are going to start by adding up the dissolution of bleaching powder and the protonation of the ClO- anion:
HCl + ClO- = HClO + Cl- | multiply with 2, you will see why in a few lines
2HCl + 2ClO- = 2HClO + 2Cl-
+
Ca(ClO)2 = Ca(2+) + 2ClO-
=
2HCl + 2ClO- + Ca(ClO)2 = Ca(2+) + 2ClO- + 2HClO + 2 Cl-
as we can see, the 2ClO- part is on both sides. We can just cross it out in this case. This leaves us at:
2HCl + Ca(ClO)2 = Ca(2+) + 2HClO + 2 Cl-
We can now combine the Ca(2+) ion and the 2 Cl- ions, because writing it that way is more elegant, but you should be aware that the CaCl2 is in solution at this stage so it would mainly be present as the two ions.
2HCl + Ca(ClO)2 = CaCl2 + 2HClO
Next we are going to add the equilibrium of HClO and HCl, but only after multiplying it with 2 again.
2HCl + Ca(ClO)2 = CaCl2 + 2HClO
+
2HCl + 2HClO = 2Cl2 + 2H2O
=
4HCl + 2HClO + Ca(ClO)2 = CaCl2 + 2HClO + 2Cl2 + 2H2O
We can once again remove something from both sides, and in this case it is the HClO. We are now done and have the final reaction:
4HCl + Ca(ClO)2 = CaCl2 + 2Cl2 + 2H2O