Question

The reaction \[2S{O_2} + {O_2} \rightleftharpoons 2S{O_3} + heat\] will be favored by
A.High temperature and low pressure
B.Low temperature and high pressure
C.High temperature and high pressure
D.Low temperature and low pressure

Answer 1

Hint: We have to know that the sulphur dioxide is a chemical compound having the molecular formula, \[S{O_2}\]. And the sulphur dioxide is a toxic compound which is responsible for the burnt matches smell. Here the sulphur is surrounded with two oxygen atoms. The sulphur has one lone pair of electrons with electron geometry trigonal planar. And the number of valence electrons present in both sulphur and oxygen is \[12\]. The rate of chemical reaction may change with change in temperature, pressure, by the presence of catalyst etc.

Complete answer:
As we know this is an exothermic reaction. Because it releases heat. Therefore, the reaction is not favored at high temperatures. And here the number of moles decreases in forward direction. Therefore, the reaction is not favored at low pressure. Hence, option (A) is incorrect.
According to the question, two moles of sulphur dioxide are reacting with one mole of oxygen and there is a formation of two moles of sulphur trioxide with liberation of heat. Hence, the reaction is an exothermic reaction in forward direction. Because, the heat is released during the reaction. Therefore, we can say that, the forward reaction of sulphur dioxide is favored in the presence of low temperature.
And here the number of moles present in the reactant side is equal to three and the number of moles present in the product side is equal to two. Which means, the number of moles is decreasing in forward reaction. Therefore, the reaction is favored at high pressure. Thus, reaction \[2S{O_2} + {O_2} \rightleftharpoons 2S{O_3} + heat\] will be favored by low temperature and high pressure. Hence, option (B) is correct.
This is an exothermic reaction. Because it releases heat. Therefore, the reaction is not favored at high temperatures. Hence, option (C) is incorrect.
Here the number of moles decreases in forward direction. Therefore, the reaction is not favored at low pressure. Hence, option (D) is incorrect.

Hence, option (B) is correct.

Note:
There are some factors that affect the reaction rates of the chemical reaction and that is, temperature, pressure, concentration of reactants, physical state of reactants and its dispersion, presence of catalyst and the solvent. The rate of a reaction increases with increasing temperature due to increasing the kinetic energy of the reactant molecules. And the rate of reaction of gaseous reactants also increases with increasing pressure due to increasing collision between the reactant molecules.