Select the word/words from the given list required to complete the following statements. Use one word only once and do not copy the complete statement.
[ammonia, carbonate, ammonium, carbon dioxide, hydrogen, hydronium, hydroxide, salt, water, precipitate]
(i) A solution M turns blue litmus red, therefore, it must contain (a) ____ ions. Another solution O turns red litmus blue, hence, it must contain (b)____ ions.
(ii) When solutions M and O are mixed, the product will be ( c) _____ and (d) ______ .
(iii) If a piece of magnesium was put into solution M (e) ___ gas would evolve.

Explanation

Let's solve the question step by step.

### Step 1: Identify the ions in solution M
- **Given**: Solution M turns blue litmus red.
- **Conclusion**: This indicates that solution M is acidic. Acids produce hydronium ions (H₃O⁺) in solution.
- **Answer**: (a) **hydronium**

### Step 2: Identify the ions in solution O
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