15 Facts on HCl + CaOCl2: What, How To Balance & FAQs

Calcium hypochlorite has a basic property and it can easily react with a strong acid like hydrochloric acid. Let us see the chemical behavior of the reaction between HCl and CaOCl2.

When hydrochloric acid reacts with calcium hypochlorite then it just follows a simple acid-base reaction mechanism. The nature of hydrochloric acid is strong enough that this reaction does not require any kind of catalyst. The reaction can occur in the laboratory with standard conditions.

There will be no need to add temperature and pressure. Now we can discuss more the mechanism of the reaction like enthalpy, redox reaction, intermolecular force, conjugate pairs, etc with an explanation in the following part of the article.

1. What is the product of HCl and CaOCl2?

When hydrochloric acid reacted with calcium oxychloride then calcium chloride will be formed as a major product along with chlorine gas and some water. The chlorine is now free from the acid molecule and calcium will attach to that chlorine part.

HCl + CaOCl2 = CaCl2(s) + H2O(l) + Cl2(g)

2. What type of reaction is HCl + CaOCl2?

The reaction between HCl + CaOCl2 is an acid-base reaction, or it can be said that it is a displacement reaction along with a redox and ionic reaction. The chlorine is displaced here and also oxidized after getting free.

3. How to balance HCl + CaCl2?

We can see CaOCl2 + HCl = CaCl2 + H2O + Cl2 reaction is not balanced here as L.H.S. and R.H.S. do have not the same number of molecules or elements, let us balance this equation in the following way,

  • Step1- Each molecule is labeled as A, B, C, D, and E as five elements are present.
  • A CaOCl2 + B HCl = D CaCl2 + C H2O + E Cl2
  • Step 2 – Now we use the equation by the suitable number which is the coefficient of reactants and products.
  • Ca = A = D, Cl = 2A + B = 2D + 2E, H = B = 2C, O = A = C
  • Step 3- all the variables and coefficients are calculated by the Gauss elimination method and we get,
  • A = 1, B = 2, C = 1, D =1, and E = 1
  • So, the overall balanced equation will be, CaOCl2 + 2HCl = CaCl2 + H2O + Cl2

4. HCl + CaOCl2 titration

To estimate the quantity of calcium we can perform titration between calcium oxychloride versus hydrochloric acid where we can follow several conditions and apparatus which are discussed below,

Apparatus used

Burette, pipette, conical flask, burette holder, volumetric flask, and two beakers.

Titer and titrant

In this titration, we used hydrochloric acid as titrant which is filled in the burette and the molecule will be analyzed with calcium oxychloride as titer which is taken in a conical flask.


We used only phenolphthalein (which is pink in basic pH and colorless in an acidic medium) because this indicator can perform better in this reaction for the ideal pH.


First, we take the burette filled with standardized hydrochloric acid and take calcium oxychloride in the conical, and added the respective indicator. Add acid dropwise with constant shaking of the flask and at the endpoint when the indicator changes its color the titration will be done.

Repeat the same process at least three to get the correct result and not down the value to a notebook and then calculate with the formula V1S1 = V2S2 to find the volume of calcium.

5. HCl + CaOCl2 net ionic equation

The net ionic equation of the chemical reaction between HCl + CaOCl2 is the formation of chloride ion along with hypochlorite ion and the acid will be ionized as proton and chloride ion, and calcium chloride salt will be ionized as Ca2+ and 2Cl which is shown below

2H+ + Cl + Ca2+ + OCl + Cl = Ca2+ + 2Cl + H+ + OH + Cl2(g)

6. HCl + CaOCl2 conjugate pairs

The conjugate pair of the reaction between HCl + CaOCl2 is the conjugate base hydrochloric acid and the respective conjugate acid of the hypochlorite salt, which is shown below,

HCl + CaOCl2 = Cl + HCaOCl+2

7. HCl and CaOCl2 intermolecular forces

The main intermolecular force between HCl + CaOCl2 is the ionic interaction of proton and chlorine ion, along with the positive charge of calcium. They attached here by two negative ion hypochlorite and chloride with H-bonding.

8. Is HCl + CaOCl2 a buffer solution?

The reaction of HCl + CaOCl2 gives us an acidic buffer in an aqueous solution as the former is a strong acid and the latter is basic salt so there will be a chance for the formation of a buffer solution at certain pH, and we get conjugate base by the reaction.

9. Is HCl + CaOCl2 a complete reaction?

The above reaction of HCl + CaOCl2 is not complete as there is no product on the right-hand side. Until we get any product on the right-hand side we cannot conclude whether the reaction will be complete or not.

CaOCl2 + 2HCl = CaCl2 + H2O + Cl2

10. Is HCl + CaOCl2 an exothermic or endothermic reaction?

The reaction between HCl + CaOCl2 is exothermic.This heat will be utilized and served as the driving force for the completion of the reaction.

11. HCl + CaOCl2 reaction enthalpy

The standard reaction enthalpy of the reaction between HCl + CaOCl2 is negative. Mathematically we can say for this reaction, δH = HProducts-Hreactans < 0.

Energy Profile Diagram for
Exothermic Reaction

12. Is HCl + CaOCl2 a redox reaction?

In the reaction between HCl + CaOCl2 there will be redox reaction mechanism observed when calcium hypochlorite is reacted with hydrochloric acid. Chlorine and oxygen will be oxidized and on the other hand calcium will be reduced along with the acid molecule.

Redox Reaction

13. Is HCl + CaOCl2 a precipitation reaction?

In the reaction HCl + CaOCl2 calcium chloride will remain insoluble in water as a form of precipitate in the aqueous solution at the conical flask’s lower part.

Precipitation Reaction

14. Is HCl + CaOCl2 reversible or irreversible reaction?

The reaction between HCl + CaOCl2 is irreversible because when the calcium chloride form from the calcium hypochlorite there is no way to form acid and calcium hypochlorite.

15. Is HCl + CaCl2 displacement reaction?

When hydrochloric acid is reacted with calcium oxychloride then the acid simply displaces the oxygen and chlorine from the hypochlorite salt.

Displacement Reaction


Calcium oxychloride is a basic salt and it is titrated with a strong acid like hydrochloric acid using indication phenolphthalein. The reaction is exothermic so need to provide any energy where the product releases energy so we will be more cautious during the reaction. After the titration, we get how much quantity of calcium chloride will be formed and then find out the quantity of calcium.

Read more about 15 Facts on HCl + AgOH and 9 Facts on HCl + Zn.

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