In carbonate hardness cations areans.Ca2+Mg2+Both Ca2+ & Mg2+Na+ Previous Marked for Review Next

Understanding Carbonate Hardness

Carbonate hardness is a measure of the concentration of calcium (Ca²⁺) and magnesium (Mg²⁺) ions in water. These ions often originate from the dissolution of carbonate minerals. When we refer to "hardness" in the context of water, it commonly denotes the presence of these divalent cations, as they contribute to the formation of scales and mineral deposits.

Main Focus of the Question

The question presents a multiple-choice format regarding the cations that are involved in carbonate hardness. The options given are:

1. Ca²⁺
2. Mg²⁺
3. Both Ca²⁺ & Mg²⁺
4. Na⁺

Analysis of Options

1. Ca²⁺: Calcium ions are a primary contributor to hardness in water, particularly carbonate hardness, as they are prevalent in many natural waters.

2. Mg²⁺: Magnesium ions also contribute significantly to carbonate hardness, as they often accompany calcium in natural waters.

3. Both Ca²⁺ & Mg²⁺: Since both cations are essential for defining carbonate hardness, this option accurately reflects the constituents of hardness in water.

4. Na⁺: Sodium ions do not contribute to hardness in water; they are associated with saltiness rather than hardness.

Conclusion

Given the contributions of Ca²⁺ and Mg²⁺ to the concept of carbonate hardness, the most accurate response is:

Final Answer

Both Ca²⁺ & Mg²⁺.