2HO HO_{2} H_{2}O_{2} H_{2}O
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Sodium bicarbonate (NaHCO_{3}) will neutralize stomach acid (HCl) in a double replacement reaction as follows: NaHCO_{3} + HCl -> NaCl + CO_{2} + \Box What is the product necessary to make this reaction complete?
Possibilities:
- 2HO
- HO_{2}
- H_{2}O_{2}
- H_{2}O

H_{2}O