Question

Which of the following reactions is not feasible?
A) $N{a_2}S{O_3} + C{O_2} \to $
B) $NaCl + {F_2} \to $
C) ${H_2}\left( g \right) + {I_2}\left( g \right) \rightleftarrows 2HI\left( g \right) + N{a_2}C{O_3} + S{O_2}\xrightarrow{\Delta }$
D) ${H_2}S + S{O_2} \to $

Answer 1

Hint: For a feasible reaction at a given temperature, it should happen unexpectedly, which implies no additional energy should be placed in for the response to happen. To see if a response is possible, you can ascertain the Gibbs free energy change for that specific response. \[\Delta G = \Delta H - T\Delta S\].
Where, \[\Delta H\] is the enthalpy change for the response.
T is the temperature at which the response is happening
\[\Delta S\] are the entropy changes related to the response.

Complete step by step answer:
We need to remember that a response possibly happens unexpectedly if the Gibbs free energy change is under zero (i.e. \[\Delta G\] is negative). This implies that exothermic responses (negative\[\Delta H\]) which bring about an expansion in entropy (positive\[\Delta S\]) will consistently be achievable at any temperature, and responses that are endothermic (positive\[\Delta H\] ) and cause a lessening in entropy (negative\[\Delta S\] ) are rarely practical, since \[\Delta G\] would be positive.
First, we see the reaction in option A.
The reaction is,
$N{a_2}S{O_3} + C{O_2} \to $
This reaction is not feasible but the reaction of $N{a_2}{S_2}{O_3}$ with carbon dioxide is possible because of the oxidation state of sulfur.
Hence option A is correct.

Note:
As we know that in regular day to day existence, something is unconstrained in the event that it occurs voluntarily, with no contribution from outside. Something very similar is valid in science; however there is one significant distinction which resists ordinary sound judgment. On the off chance that you drop marble chips (calcium carbonate) to weaken hydrochloric corrosive, there is a prompt effervescing. You don't have to do whatever else - the response happens totally voluntarily. It is an unconstrained change. However, in science, an unconstrained change doesn't need to be fast; truth be told, it tends to be incredibly, slow for sure - even vastly moderate. For instance, carbon consumes in oxygen to make carbon dioxide, yet a bit of carbon will remain absolutely unaltered anyway long you keep it except if you first warm it. The energetics is appropriate for a response to occur, however there is tremendous initiation energy.