Question

After the quench step, the pH is checked. If the solution is acidic (paper turns purple), how can you neutralize the solution?

a. Add sodium hydroxide (NaOH)
b. Add hydrochloric acid (HCl)
c. Add potassium iodide (KI)
d. Add sodium carbonate (Na2CO3)

Answer 1

To neutralize an acidic solution indicated by the pH paper turning purple, sodium hydroxide (NaOH) option (a) should be added, as it is a strong base that will increase the pH of the solution towards neutral.

Step-by-step explanation:

If the solution is acidic (as indicated by the pH paper turning purple), you can neutralize the solution by adding a base. In this case, the correct choice would be to add sodium hydroxide (NaOH), which is a strong base and will react with the excess acid in the solution to form water and salt, thus increasing the pH of the solution towards neutral.

On the other hand, adding hydrochloric acid (HCl) would further lower the pH, making the solution even more acidic. Potassium iodide (KI) is a neutral salt and will not affect the pH, while sodium carbonate (Na2CO3) is a basic salt but not as strong as NaOH. For quick neutralization, NaOH would be the most effective.