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 KClO3, 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 H2SO4.
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+ + SO42- + 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 = SO42-
- 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.
Molecule | Acting force |
H2SO4 | Electrostatic, van der waal’s Dipole interaction |
KClO3 | Strong electrostatic force and ionic interaction, Coulumbic force |
KHSO4 | Electrostatic force, ionic interaction, |
HClO4 | Covalent, H-bonding, van der waal’s interaction |
ClO2 | Van der Waal’s interaction, and covalent force |
H2O | H-bonding, ionic interaction |
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.
Molecule | Enthalpy (KJ/mol) |
KClO3 | -391.2 |
H2SO4 | -814 |
KHSO4 | -1163.3 |
H2O | -68 |
HClO4 | 13.5 |
ClO2 | 101.3 |
and Products
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.
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.