Question

If the level of free chlorine is too high, what chemical can you add to reduce the level of free chlorine?

A) Sodium Hypochlorite
B) Soda ash/ Sodium Carbonate
C) Sodium Thiosulfate
D) Muriatic Acid

Answer 1

Sodium Thiosulfate (Choice C) can be added to reduce the level of free chlorine.

Step-by-step explanation:

If the level of free chlorine is too high, the chemical that can be added to reduce the level of free chlorine is Sodium Thiosulfate (Choice C).

When sodium thiosulfate is added to water, it reacts with the excess chlorine to form sodium sulfate and harmless chloride ions. This reaction reduces the concentration of free chlorine in the water.

In equation form, the reaction can be represented as:

2Na2S2O3 + 2Cl2 → 2NaCl + Na2S4O6