Which chemical has a purity of 0.98 and is known for its higher solubility with higher temperature?

The correct answer relates to sodium fluoride, which has a purity of 0.98 and exhibits higher solubility in water as the temperature increases. This property is significant in various applications, especially in water treatment processes where temperature variations can impact how well a chemical dissolves in water.

Sodium fluoride is often used in fluoridation processes to improve dental health, and its ability to dissolve more readily at higher temperatures makes it effective for ensuring adequate fluoride levels in water supplies. The solubility characteristics of sodium fluoride allow for flexibility in its application, particularly in warmer environments or seasons when water temperatures rise.

Understanding the solubility behavior of chemicals like sodium fluoride can help water operators effectively manage chemical dosing and ensure that water treatment processes achieve desired outcomes without excessive residue or undissolved material, which could lead to operational inefficiencies or negative impacts on water quality.