Answer:
Sodium bicarbonate acted as a pH buffer in Solution 2.
Step-by-step explanation:
One the other hand, sodium bicarbonate is alkaline in nature and has pH of 8.4. When an acid is added to a solution containing sodium bicarbonate, it will act as a pH buffer for acid and neutralize the acidic effect.
Other options are incorrect because there are no hormones added neither they will be produced or released during the reaction.
Also, lower initial pH of the solution 1 will not help to increase the pH after addition of acid.
Neither change in temeprature can change the pH.