Potassium, sodium, calcium react with cold water liberating ____ and forming the corresponding ____ .

Explanation

To answer the question, we need to analyze the reactions of potassium, sodium, and calcium with cold water.

### Step-by-Step Solution:

1. **Identify the Metals**: The metals mentioned are potassium (K), sodium (Na), and calcium (Ca). These are all highly reactive metals.

2. **Reactions with Cold Water**:
- **Potassium Reaction**:
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