Potassium sulfate, an inorganic salt, tends to react with strong acids such as Hydrochloric acid. Let us look into how their reaction occurs.

Hydrochloric acid (HCl) is a strong acid for it can completely dissociate in water, and is a colorless solution with a pungent odor. Its physical properties vary with concentration. Potassium sulfate (K₂SO₄) is a water-soluble white crystalline solid that, when reacted with HCl, forms an alkali metal salt and an acid.

Let us go through the products of the reaction between HCl and K₂SO₄, the enthalpy of the reaction, the reaction type, and so on in depth in the following sections.

What is the product of HCl and K₂SO₄

HCl and K₂SO₄ are reacted to form Sulfuric acid and Potassium chloride respectively. The chemical reaction is as follows:

2HCl (aq) + K₂SO₄ (aq) = H₂SO₄ (aq) + 2KCl (aq)

What type of reaction is HCl + K₂SO₄

K₂SO₄ with HCl is a Double displacement (Metathesis) reaction.

How to balance HCl + K₂SO₄

The skeletal unbalanced chemical equation is: HCl + K₂SO₄ = H₂SO₄ + KCl

The following are the steps to equate the reaction mentioned above:

• The number of atoms of elements present on both the reactant and product sides must be equal for the reaction to be balanced.

• According to the preceding table, the only unbalanced atoms in this reaction are K and H. Stoichiometric coefficients are added to molecules as needed.
• Here, the compounds containing chlorine, i.e., HCl and KCl, are multiplied by coefficient 2, balancing the whole chemical equation.
• The balanced chemical reaction is:

2HCl + K₂SO₄ = H₂SO₄ + 2KCl

HCl + K₂SO₄ Titration

K₂SO₄ cannot be titrated against HCl because no significant color change will be detected even when an indicator such as Phenolphthalein or Methyl orange is used. It is considered a neutral salt that is colorless in an acidic solution.

HCl + K₂SO₄ Net Ionic Equation

• The complete ionic equation for HCl + K₂SO₄ is as follows:

2K⁺ (aq) + SO₄^2- (aq) + 2H⁺ (aq) + 2Cl^– (aq) = 2K⁺ (aq) + 2Cl^– (aq) + 2H⁺ (aq) + SO₄^2- (aq)

• However, the net ionic equation comprises only those species that are taking part in the reaction, eliminating the spectator ions; as all of the ions are spectator ions in the reaction between HCl and K₂SO₄, thus, there is no reaction.

HCl + K₂SO₄ Conjugate Pairs

• The conjugate base of HCl is Cl^– as HCl being a strong acid, donates a proton to form a Cl^– ion.
• SO₄^2- is a weak base that accepts a proton (H⁺) to form its conjugate acid HSO₄^2-.

HCl + K₂SO₄ Intermolecular Forces

• The Intermolecular forces observed in HCl are dipole-dipole interaction and London dispersion forces, with dipole-dipole interactions being stronger. K₂SO₄ is composed of ions hence the intermolecular forces of attraction present in K₂SO₄ are ionic forces.
• For the products formed, H₂SO₄ shows the presence of Van der waals dispersion forces, dipole-dipole interactions and strong intermolecular hydrogen bonding forces. The intermolecular interaction in KCl is ionic forces.

HCl + K₂SO₄ Reaction Enthalpy

The Enthalpy of the reaction between K₂SO₄ and HCl is evaluated as 95.1 kJ/mol.

The Reaction enthalpy is calculated using the formula: ΔH⁰_{f (reaction)} = ΣΔH⁰_{f (products)} – ΣΔH⁰_{f (reactants)}

Is HCl + K₂SO₄ a Buffer Solution

The reaction HCl + K₂SO₄ does not behave as a buffer because of the presence of a strong acid, and secondly, KCl obtained as a product is a salt of strong acid, so a noticeable pH change would be observed.

Is HCl + K₂SO₄ a Complete Reaction

HCl + K₂SO₄ is a complete reaction as both the products formed are completely ionized and are soluble in water; thereby, it will not undergo any further reactions.

Is HCl + K₂SO₄ an Exothermic or Endothermic Reaction

The reaction HCl + K₂SO₄ is an endothermic reaction due to its positive enthalpy change. As a result, a considerable amount of energy is absorbed to carry out the reaction.

Is HCl + K₂SO₄ a Redox Reaction

HCl + K₂SO₄ is not a redox reaction since no change in oxidation state is observed for any of the reacting atoms of elements.

Is HCl + K₂SO₄ a Precipitation Reaction

K₂SO₄ with HCl is not a precipitation reaction since both products formed after completion of the reaction are highly soluble in water, so no precipitate will develop.

Is HCl + K₂SO₄ Reversible or Irreversible Reaction

HCl + K₂SO₄ reaction is irreversible in nature because the products formed cannot react again to give back the reactants under the same conditions.

Is HCl + K₂SO₄ Displacement Reaction

The reaction of K₂SO₄ with HCl occurs via Displacement. The reaction mechanism it undergoes is an example of Double displacement (metathesis) reaction wherein the reactant ions exchange with each other to generate two new compounds.

Conclusion

HCl and K₂SO₄ both function as significant laboratory reagents. K₂SO₄ is a powerful electrolyte that reacts with HCl to give KCl and H₂SO₄. KCl is used in agricultural fertilizer manufacture. It is also used in water softener units and in the making of soaps. H₂SO₄ is a vital catalyst in the chemical industry.

Padmakshi Kotoky

Hello, I am Padmakshi Kotoky working as a Subject Matter Expert on this platform. I have completed my post-graduation from the Institute of Chemical Technology, Mumbai. I have always found Chemistry an intriguing subject and enjoy exploring more on it. I would like to utilize this platform to explain the subject in an easy and precise manner making it simpler for the readers to understand the concepts with clarity. I engage myself in Singing, Dancing, and nature photography during my leisure time.
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