There are certain reactions which show certain colour change in the product. Let us look at such beautiful reactions and their properties.
Sulphuric acid, hygroscopic and colourless, is a lab reagent that is corrosive in nature. Potassium Sulphide is also hygroscopic and a toxic compound having high solubility in water but low in organic solvents. Dusts of sulphide are harmful for our eyes and skin. The reaction produces products in different states.
This article will show how the reaction of two dangerous compound give products of varying properties.
What is the product of H2SO4 and K2S?
H2SO4 and K2S are reacted to form Potassium sulphate, sulphur dioxide gas, sulphur and water molecule respectively. The reaction equation is:
- 2H2SO4 + K2S → K2SO4 + SO2 + S + 2H2O
What type of reaction is H2SO4 + K2S?
The reaction of H2SO4 and K2S is a dissociation reaction as products formed dissociate to ions in the solution.
How to balance H2SO4 + K2S?
These are the rules to equal the H2SO4 + K2S reaction scheme:
- H2SO4 + K2S → K2SO4 + SO2 + S + H2O
- Here, both the reaction and product side must be equal in atoms; multiply H2SO4 with 2 to equal with the sulphur atoms of H2SO4.
- 2H2SO4 + K2S → K2SO4 + SO2 + S + 2H2O
H2SO4 + K2S Titration
H2SO4 + K2S titration is possible and should be carried out with caution.
Apparatus
- Graduated burette
- Conical flask
- Volumetric flask
- Burette stands
- Sample beakers
Titre and Titrant
- K2S is used as the titrant, whose concentration is known.
- H2SO4 is the titre, the concentration is to be measured.
Indicator
Thymol Blue indicator is used for strong acid-base titrations as it turns yellowish in an acidic medium while bluish in a basic medium.
Procedure
- Standardised solution of K2S of known concentration is filled in the burette and clamped to the stand.
- In the conical flask, the unknown sulphuric acid is added after washing.
- Few drops of thymol blue indicator(pH= 8.0-9.6) is added in the solution.
- At the equivalence point, equal moles of acid and base have reacted, signifying the end of the titration with suitable colour change.
- The volume of base used is applied to measure the strength of the acid by the formula:
- VK2S SK2S = VH2SO4 SH2SO4
H2SO4 + K2S Net Ionic Equation
H2SO4 + K2S reaction has the net ionic equation,
- 2H+(aq) + 2SO42-(aq) + 2K+(aq) + S2-(aq) → 2K+(aq) + SO42-(aq) + SO2(g) + S(g) + H+(aq) + OH–(aq)
H2SO4 + K2S Conjugate Pairs
H2SO4 + K2S reaction has the following conjugate pairs:
- Conjugate base of H2SO4= HSO4–
- Conjugate base of H2O= OH–
H2SO4 + K2S Intermolecular Forces
H2SO4 + K2S reaction has the following intermolecular forces,
- H2SO4 shows an ionic character in an aqueous medium.
- K2S show weak intermolecular forces like Van der Waals forces.
- K2S is more prone to reaction with water.
- S consists of allotropes in rhombic and monoclinic form.
H2SO4 + K2S Reaction Enthalpy
H2SO4 + K2S reaction enthalpy is around -272 kJ/mol. The enthalpy information is as follows:
- Enthalpy of Formation of K2S = -406.2 kJ/mol
- Enthalpy of Formation of H2SO4 = -814 kJ/mol
- Enthalpy of Formation of H2O = -285.8 kJ/mol
- Enthalpy of Formation of K2SO4 = -1437.7 kJ/mol
- Enthalpy of Formation of S = 0 (element)
- Enthalpy of Formation of SO2 = -296.8 kJ/mol
Is H2SO4 + K2S a Buffer Solution?
H2SO4 + K2S cannot be a strong buffer solution because it strong acids like sulphuric acid cannot make a buffer.
Is H2SO4 + K2S a Complete Reaction?
The H2SO4 + K2S reaction can be called complete as, once equilibrium is reached, products are completely formed.
Is H2SO4 + K2S an Exothermic Reaction?
H2SO4 + K2S reaction is exothermic in nature as the value is negative.
Is H2SO4 + K2S a Redox Reaction?
The reaction of H2SO4 and K2S is an actual redox reaction because:
- Oxidation state of Sulphur changes from -2 to 0 in the products.
- K2S(-2) → S(0)
Is H2SO4 + K2S a Precipitation Reaction?
H2SO4 + K2S is not a precipitation reaction because no precipitate is obtained. Instead, gaseous products are obtained.
Is H2SO4 + K2S a Reversible Reaction?
H2SO4 + K2S reaction is not reversible in nature as final products obtained are gases that cannot revert.
Is H2SO4 + K2S a Displacement Reaction?
H2SO4 + K2S reaction is not a displacement reaction as no ions are replaced in the products while reactants have decomposed.
Conclusion
H2SO4 is both a good oxidising and dehydrating agent that is non-flammable in nature. K2S, insoluble in ether, is another useful lab reagent that loves to react with water. The acid-base titration reflects the usage of indicators to form the desired product.
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