Which alternative can be used for softening that removes both carbonate and noncarbonate hardness?

Which alternative can be used for softening that removes both carbonate and noncarbonate hardness?

• A. Calcium carbonate
• B. Zinc sulfate
• C. Sodium hydroxide
• D. Aluminum sulfate

Answer: (C)

Sodium hydroxide is an effective alternative for water softening because it reacts with both carbonate and noncarbonate hardness. In the context of water treatment, carbonate hardness is primarily due to the presence of calcium and magnesium bicarbonates, while noncarbonate hardness typically involves sulfates and chlorides of calcium and magnesium. When sodium hydroxide is added to water containing hardness, it increases the pH level, which promotes the precipitation of calcium and magnesium as their respective hydroxides. This process effectively removes both types of hardness from the water, resulting in a softened product. Additionally, sodium hydroxide can help convert any soluble bicarbonates to insoluble carbonates, facilitating their removal through sedimentation or filtration. This method is particularly valuable in water treatment facilities where the goal is to achieve a lower hardness level for the distribution of potable water or for use in industrial processes. The ability to address both carbonate and noncarbonate hardness makes sodium hydroxide a versatile chemical in softening applications.

Sodium hydroxide is an effective alternative for water softening because it reacts with both carbonate and noncarbonate hardness. In the context of water treatment, carbonate hardness is primarily due to the presence of calcium and magnesium bicarbonates, while noncarbonate hardness typically involves sulfates and chlorides of calcium and magnesium.

When sodium hydroxide is added to water containing hardness, it increases the pH level, which promotes the precipitation of calcium and magnesium as their respective hydroxides. This process effectively removes both types of hardness from the water, resulting in a softened product. Additionally, sodium hydroxide can help convert any soluble bicarbonates to insoluble carbonates, facilitating their removal through sedimentation or filtration.

This method is particularly valuable in water treatment facilities where the goal is to achieve a lower hardness level for the distribution of potable water or for use in industrial processes. The ability to address both carbonate and noncarbonate hardness makes sodium hydroxide a versatile chemical in softening applications.