Answer:
Option B, Because of the reversible nature of crystallizing and dissolving
Explanation:
Solution containing the maximum amount of solute that can be dissolved in the given solvent at the particular temperature is called saturated solution.
Reversible reaction is the reaction which can go in reverse and forward direction both on varying reaction condition.
In the saturated NaCl solution, on lowering temperature, The the dissolved NaCl molecules may crystallize. Likewise on increasing temperature, the crystallized crystals may dissolved. As the reaction moves in both the direction, therefore its considered to be equilibrium system.
Therefore, amog given, option B is correct.
Because of the reversible nature of crystallizing and dissolving
Answer:The correct answer is ;
The oxidation state of nitrogen in NO changes from +2 to 0, and the oxidation state of carbon in CO changes from +2 to +4 as the reaction proceeds.
Explanation:

In an oxidation recation addition of oxygen atom takes place or loss of electrons takes place.
In an reduction reaction removal of oxygen atom takes place or gain of electrons takes place.
In the given reaction , the nitrogen atom is present in +2 oxidation state in NO molecule and present in 0 oxidation state in
molecule. Hence, nitrogen is getting reduced that is reduction reaction. NO is oxidizing agent
In the given reaction , the carbon atom is present in +2 oxidation state in CO molecule and present in +4 oxidation state in
molecule. Hence ,carbon is getting oxidized that is oxidation reaction. CO is a reducing agent.
HI acts as an arrhenius acid in solution. It will dissociate into H⁺ and I⁻ therefore being a proton donor. (HI is actually one of the 7 strong acids)
I hope this helps.