What is the term for the general condition of water determined by dissolved minerals and ions such as calcium and magnesium?

What is the term for the general condition of water determined by dissolved minerals and ions such as calcium and magnesium?

• A. Turbidity
• B. pH
• C. Dissolved Oxygen
• D. Hardness of Water

Answer: (D)

Hardness of water describes how much dissolved minerals, especially calcium and magnesium ions, are present in the water. These ions come from rocks and soil, and higher levels make water “hard.” This term captures the idea that minerals dissolved in water—not CO2, not organic material—define its condition in this context. Hard water is what causes soap to form less lather and leaves scale in kettles and pipes. There are two forms: temporary hardness, from hydrogencarbonates, which can be removed by boiling; and permanent hardness, from sulfates and chlorides of calcium and magnesium, which boiling can’t remove. Hardness is commonly expressed as mg/L of calcium carbonate equivalents. In contrast, turbidity is about cloudiness from suspended particles, pH is about how acidic or basic the water is, and dissolved oxygen is about how much oxygen gas is dissolved in the water.

Hardness of water describes how much dissolved minerals, especially calcium and magnesium ions, are present in the water. These ions come from rocks and soil, and higher levels make water “hard.” This term captures the idea that minerals dissolved in water—not CO2, not organic material—define its condition in this context. Hard water is what causes soap to form less lather and leaves scale in kettles and pipes. There are two forms: temporary hardness, from hydrogencarbonates, which can be removed by boiling; and permanent hardness, from sulfates and chlorides of calcium and magnesium, which boiling can’t remove. Hardness is commonly expressed as mg/L of calcium carbonate equivalents. In contrast, turbidity is about cloudiness from suspended particles, pH is about how acidic or basic the water is, and dissolved oxygen is about how much oxygen gas is dissolved in the water.