Sodium hydroxide (NaOH) was added to pure water (H2O). Which most likely were the pH values of the water before and after the sodium hydroxide was added to it?

Abefore = 7, after = 9
Bbefore = 7, after = 4
Cbefore = 4, after = 7
Dbefore = 9, after = 7

Verified Answer :

Before 7 after 9. A pH smaller than 7 indicates acidity with 0 being completely acidic. A pH greater than 7 shows alkalinity with 14 being completely alkaline. 7 is neutral. Since NaOH is alkaline, adding it to a neutral substance would increase the pH and it would increase from 7 to 9.

Answer:

A before = 7, after = 9

Explanation: