15 Facts on H2SO4 + KClO3: What, How To Balance & FAQs

KClO₃ is a salt of strong base called potassium hydroxide, so it can easily react with a strong acid like H₂SO₄. Let us see the details of the reaction between KClO₃ and H₂SO₄.

On the thermal decomposition of potassium chlorate, we get oxygen gas. So it is a commercial reagent for the preparation of O₂. The oxidation state of potassium in KClO₃ is +1, so it is a very strong oxidizing agent where the oxidation state of Cl is +5. Sulfuric acid is also a powerful oxidizing agent.

By the reaction between H₂SO₄ and KClO_3, we can estimate the quantity of potassium. Let us discuss the mechanism of the reaction between sulfuric acid and potassium chlorate, the reaction enthalpy, the type of reaction, product formation, etc. in the following part of the article.

1. What is the product of H₂SO₄ and KClO₃?

Potassium hydrogen sulfate and perchloric acid are formed as major products when H₂SO₄ and KClO₃ are reacted together. There is also some chlorine dioxide formed as a by-product along with water molecules.

2. What type of reaction is H₂SO₄ + KClO₃?

H₂SO₄ + KClO₃ reaction is an example of an acid formation reaction and double displacement reaction along with redox and precipitation reactions. Here, acid compounds are formed in the course of the reaction along with water.

3. How to balance H₂SO₄ + KClO₃?

H₂SO₄ + KClO₃ = KHSO₄ + HClO₄ + ClO₂ + H₂O reaction is not balanced yet, we have to balance the equation in the following way-

• First, we label all the reactants and products by A, B, C, D, E, and F as there are six different molecules obtained for this reaction and the reaction looks like this: A H₂SO₄ +B KClO₃ = C KHSO₄ + D HClO₄ + E ClO₂ + F H₂O
• Equate the coefficients for the same type of elements by rearranging them.
• After the rearrangement of coefficients of the same elements by their stoichiometric proportion, we get: H = 2A = C = D = 2F, S = A = C, O = 4A = 3B = 4C = 4D = 2E = F, K = B= C, Cl = B = D = E,
• Using the Gaussian elimination and equating all the equations we get, A = 3, B = 3, C = 3, D = 1, E = 2, and F =1,
• The overall balanced equation will be,
  • 3 H₂SO₄ +3 KClO₃ = 3 KHSO₄ +  HClO₄ + 2 ClO₂ +  H₂O

4. H₂SO₄ + KClO₃ titration

To estimate the quantity of potassium or chlorine we can perform a titration between KClO₃ and H₂SO_4.

Apparatus used

We need a burette, conical flask, burette holder, volumetric flask, and beakers for this titration.

Titre and titrant

H₂SO₄ acts as a titrant which is taken in the burette and the molecule to be analyzed is KClO₃ which is taken in a conical flask.

Indicator

The whole titration is done in an acidic medium or acidic pH so the best suitable indicator will be phenolphthalein which gives perfect results for this titration at given pH.

Procedure

The burette is filled with standardized H₂SO₄. KClO₃ is taken in a conical flask along with respective indicators. H₂SO₄ is added dropwise to the conical flask and the flask is shaken constantly. After a certain time, when the endpoint arrives, the indicator changes its color and the reaction is done.

We repeat the titration several times for better results and then we estimate potassium as well as chlorine quantity by the formula V₁S₁ = V₂S₂.

5. H₂SO₄+ KClO₃ net ionic equation

The net ionic equation between H₂SO₄ + KClO₃ is as follows,

2H⁺ + SO₄^2- + K⁺ + ClO₃^– = K⁺ + HSO₄^– + H⁺ + ClO₄^– + ClO₂ + H⁺ + OH^–

To derive the net ionic equation, the following steps are required,

• H₂SO₄ will be ionized in proton and sulfate ions as it is a strong electrolyte
• After that KClO₃ also dissociates into K⁺ ion and ClO₄– ion as it is also a strong electrolyte
• In the product part, the salt KHSO₄ is also dissociated into K⁺ and HSO₄^–, and bisulfate can also be dissociated into H⁺ and sulfate ions.
• Perchloric acid is also ionized as H⁺ and ClO₄^–.
• And lastly, water is dissociated into a proton and hydroxide ions.

6. H₂SO₄+ KClO₃ conjugate pairs

In the reaction, H₂SO₄ + KClO₃ conjugate pairs will be the corresponding de-protonated and protonated form of that particular species which are listed below-

• Conjugate pair of H₂SO₄ = SO₄^2-
• Conjugate pair of OH^– = H₂O
• Conjugate pair of ClO₄^– = HClO₄
• Conjugate pair of KHSO₄ = KSO₄^–

7. H₂SO₄ and KClO₃ intermolecular forces

The intermolecular force present in H₂SO₄ is the electrostatic force between protons and sulfate ions. In KClO₃, there are electronic interactions and coulumbic force present.

8. H₂SO₄ + KClO₃ reaction enthalpy

H₂SO₄ + KClO₃ reaction enthalpy is +273.8 KJ/mol which can be obtained by the formula: enthalpy of products – enthalpy of reactants. Here the change in enthalpy is positive.

9. Is H₂SO₄ + KClO₃ a buffer solution?

The reaction between H₂SO₄ + KClO₃ gives a buffer solution of KHSO₄ and HClO₄ because they can control the pH of the reaction as the former is basic salt and the latter is acid.

10. Is H₂SO₄ + KClO₃ a complete reaction?

The reaction between H₂SO₄ + KClO₃ is complete because it gives two major and two side products.

11. Is H₂SO₄ + KClO₃ an exothermic or endothermic reaction?

The reaction of H₂SO₄ + KClO₃ is endothermic in terms of thermodynamics first law. This reaction absorbs more energy and temperature from the surroundings which helps to complete the reaction, Where δH is always positive.

12. Is H₂SO₄ + KClO₃ a redox reaction?

H₂SO₄ + KClO₃ reaction is a redox reaction because in this reaction many elements get reduced and oxidized as K gets reduced and S and Cl get oxidized here.

13. Is H₂SO₄ + KClO₃ a precipitation reaction?

The reaction between H₂SO₄ + KClO₃ is a precipitation reaction because KHSO₄ gets precipitated in the solution and is not soluble in the reaction mixture.

14. Is H₂SO₄ + KClO₃ reversible or irreversible reaction?

The reaction between H₂SO₄+ KClO3 is irreversible because it produces salt, acid, and one gaseous molecule ClO₂ which can increase the entropy of the reaction and shift the equilibrium towards the right-hand side only forward directions.

15. Is H₂SO₄ + KClO₃ displacement reaction?

The reaction between H₂SO₄+ KClO₃ is an example of a double displacement reaction because in the above reaction H+ displaced K⁺ from KClO₃ and again K⁺ displaced H⁺ from H₂SO₄.

Conclusion

The reaction between H₂SO₄ and KClO₃ gives us an electrolytic salt potassium bisulfate along with perchloric acid, where we can estimate the amount of chlorine. This reaction is an acid-base and irreversible reaction. This reaction is used for the production of perchloric acid.

Biswarup Chandra Dey

Hi……I am Biswarup Chandra Dey, I have completed my Master’s in Chemistry from the Central University of Punjab. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.