Reaction between potassium dichromate and sulphir dioxide gas?
The reaction between potassium dichromate (K2Cr2O7) and sulfur dioxide gas (SO2) results in the formation of chromic acid (H2CrO4), potassium sulfate (K2SO4), and water (H2O).
To understand the reaction, it is essential to know the balanced chemical equation:
K2Cr2O7 + 3SO2 + H2O → 2H2CrO4 + K2SO4
Now, let's break down the reaction to understand what is happening step by step:
1. Start with the reactants: Potassium dichromate (K2Cr2O7) and sulfur dioxide gas (SO2).
2. The potassium dichromate, which is a powerful oxidizing agent, reacts with sulfur dioxide (a reducing agent).
3. In the reaction, the sulfur dioxide (SO2) is oxidized to form sulfur trioxide (SO3) and sulfuric acid (H2SO4), but due to the presence of water, the sulfur trioxide (SO3) instantly reacts with water to form sulfuric acid (H2SO4).
SO2 + H2O → H2SO4
4. At the same time, potassium dichromate (K2Cr2O7) is reduced to chromic acid (H2CrO4).
K2Cr2O7 + 6H2O → 2H2CrO4 + 2KOH
5. Finally, as the reaction proceeds, potassium sulfate (K2SO4) and water (H2O) are formed as by-products.
2KOH + H2SO4 → K2SO4 + 2H2O
It is important to note that this reaction needs to occur under specific conditions such as heating and in the presence of a catalyst like sulfuric acid. Additionally, since this reaction involves toxic and corrosive substances, it should only be carried out in a controlled laboratory setting by trained individuals.