Answer:
I Think this answer will help
Explanation:
Soda ash/sodium hydroxide injection
This treatment method is used if water is acidic (low pH). Soda ash (sodium carbonate) and sodium hydroxide raise the pH of water to near neutral when injected into a water system. Unlike neutralizing filters, they do not cause hardness problems in treated water.
I think it would be the thrid
Answer: This is called chlorine
Explanation: 18