Solution : An oxidation reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between tow species an oxidaion reductin reaction is any chemical reaction in which the oxidation number of a molecule atom or ion changes by gaining or losing an electron
Answer: b.
is positive and
is positive.
Explanation:-
As the temperature of the pack drops, the energy has been absorbed from the pack for dissolution of
in water. Thus as the energy has been absorbed in the reaction, the reaction is endothermic and the change in enthalpy i.e.
is positive.
The entropy is the measure of degree of randomness. The entropy increases when the randomness increases and the entropy decreases when the randomness decreases. When a substance dissolves in water, it dissociate into ions and hence the randomness increases thus the change in entropy i.e.
is positive.