Water that does not contain compounds of calcium and magnesium.

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Question:**
The question asks for the type of water that does not contain compounds of calcium and magnesium.

2. **Definition of Hard Water:**
Hard water is defined as water that contains high concentrations of calcium and magnesium compounds, such as bicarbonates, carbonates, and sulfates. This type of water does not produce foam when mixed with soap or detergent.

3. **Definition of Soft Water:**
In contrast, soft water is defined as water that has low concentrations of calcium and magnesium compounds. This type of water is capable of producing foam when mixed with soap or detergent.

4. **Conclusion:**
Therefore, the type of water that does not contain compounds of calcium and magnesium is known as **soft water**.