KOH can easily react with a strong base like H2SO4. Let us discuss the reaction between H2SO4 and KOH.
Potassium hydroxide is one of the strongest bases because it is a hydroxide of alkali metal. It can easily release hydroxide ions in an aqueous solution so it is Arrhenius base. Hot and concentrated sulfuric acid when reacted with a strong base neutralized KOH by forming salt and water molecule.
Let us discuss the mechanism of the reaction between sulfuric acid and iron, 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 KOH?
Potassium sulfate is a major product formed when H2SO4 and KOH are reacted together along with water molecules.
H2SO4 and KOH
2. What type of reaction is H2SO4 + KOH?
H2SO4 + KOH reaction is an example of a neutralization reaction and double displacement reaction along with redox and precipitation reactions. Here, acid compounds neutralize alkali compounds and form salt and water.
3. How to balance H2SO4 + KOH?
H2SO4 + KOH = K2SO4 + 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, and D as there are only four molecules obtained for this reaction and the reaction looks like this: A H2SO4 + B KOH = C K2SO4 + D H2O
- Equating 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 = B = D, S = A = B, O = 4A = B = 4C = D, K = B = 2C.
- Using the Gaussian elimination and equating all the equations we get, A = 1, B = 2, C = 1, and D = 2, so the oxidation number of Fe is +2 on both sides.
- The overall balanced equation will be,
H2SO4 + 2KOH = K2SO4 + 2H2O
4. H2SO4 + KOH titration
To estimate the quantity of sulfur or copper we can perform a titration between KOH 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 KOH which is taken in a conical flask.
Indicator
The whole titration is done in two mediums:- first basic and then 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. Fe 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 the iron as well as sulfate quantity by the formula V1S1 = V2S2.
5. H2SO4+ KOH net ionic equation
The net ionic equation between H2SO4 + KOH is as follows,
2H+ + SO42- + 2K+ + 2OH– = 2K+ + SO42- + 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 KOH also dissociates into potassium ions and hydroxide ions as it is a strong base.
- The salt K2SO4 also dissociate into K+ and sulfate ions as it is a strong electrolyte.
- And lastly water is ionized into H+ and OH–.
6. H2SO4+ KOH conjugate pairs
In the reaction, H2SO4 + KOH 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
7. H2SO4 and KOH intermolecular forces
The intermolecular force present in H2SO4 is the strong electrostatic force between protons and sulfate ions. There is also strong ionic interaction present in KOH and for K2SO4, there is ionic interaction and coulumbic force. In water H-bonding is present.
| Molecule | Acting force |
| H2SO4 | Electrostatic, van der waal’s Dipole interaction |
| KOH | Strong electrostatic force and ionic interaction |
| K2SO4 | Columbia force, ionic interaction |
| H2O | Covalent, H-bonding |
8. H2SO4 + KOH reaction enthalpy
H2SO4 + KOH reaction enthalpy is +87.34 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) |
| KOH | -423.57 |
| H2SO4 | -814 |
| K2SO4 | -1437.8 |
| H2O | -68 |
and Products
9. Is H2SO4 + KOH a buffer solution?
The reaction between H2SO4 + KOH gives a buffer solution of K2SO4 and H2O and they can control the pH of the reaction.
10. Is H2SO4 + KOH a complete reaction?
The reaction between H2SO4 + KOH is a complete reaction because it neutralized two reactants by forming one complete product K2SO4 along with H2O.
11. Is H2SO4 + KOH an exothermic or endothermic reaction?
The reaction of H2SO4 + KOH is endothermic in terms of thermodynamics first law. This reaction releases more energy and temperature to the surroundings which help to complete the reaction, where δH is always positive.
12. Is H2SO4 + KOH a redox reaction?
H2SO4 + KOH reaction is a redox reaction because in this reaction many elements get reduced and oxidized as potassium gets reduced and sulfur gets oxidized.
between H2SO4 and KOH
13. Is H2SO4 + KOH a precipitation reaction
The reaction H2SO4 + KOH is not a precipitation reaction because the formation of salt K2SO4 is soluble in water and nothing is precipitated.
14. Is H2SO4 + KOH reversible or irreversible reaction?
The reaction between H2SO4+ KOH is irreversible because it is one kind of acid-base reaction.
15. Is H2SO4 + KOH displacement reaction?
The reaction between H2SO4+ KOH is an example of a double displacement reaction because in the above reaction K+ displaced H+ in H2SO4 and H+ displaced K+ in KOH.
Conclusion
The reaction between H2SO4 and KOH gives us an electrolytic salt potassium sulfate where we can estimate the amount of potassium present. This reaction is an acid-base and irreversible reaction, and we also estimate the strength of the base or acid.
Read more facts on H2SO4:
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.