\(2SO_2 (g) + O_2 (g) \overset{V_2O_5}{\longrightarrow} 2SO_3 (g)\, \ \Delta H = -196.6\text{kJ mol}^{-1} \)
For the above given reaction, identify the incorrect statement from the following
Answer & explanation
Correct answer: option 3
The correct answer is option 3. The forward reaction leads to an increase in volume.
Let us analyze the given reaction and statements:
\[2SO_2 (g) + O_2 (g) \overset{V_2O_5}{\longrightarrow} 2SO_3 (g)\, \ \Delta H = -196.6\text{ kJ mol}^{-1}\]
Statements:
(1) It is an exothermic reaction:
The negative value of \(\Delta H\) (-196.6 kJ/mol) indicates that the reaction releases heat. Therefore, Statement (1) is correct.
(2) It is a reversible reaction:
The presence of the reversible arrow (\(\overset{V_2O_5}{\longrightarrow}\)) indicates that the reaction is reversible. So, Statement (2) is correct.
(3) The forward reaction leads to an increase in volume:
To determine the change in volume, we need to consider the stoichiometry of the reaction. The reaction involves two moles of \(SO_2\) and one mole of \(O_2\) on the reactant side and two moles of \(SO_3\) on the product side. As a result, the forward reaction leads to a decrease in the number of moles of gas, and according to Avogadro's principle, this corresponds to a decrease in volume. Therefore, Statement (3) is incorrect.
(4) The forward reaction leads to a decrease in volume:
This statement is correct based on the explanation provided above.
Conclusion:
The incorrect statement is (3) "The forward reaction leads to an increase in volume."