Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
Which chemical substance is used in the treatment of hard water to remove temporary hardness?
Calcium Carbonate
Calcium Hydroxide
Sodium Chloride
Potassium Permanganate
Calcium Hydroxide
Calcium hydroxide, commonly known as slaked lime, is used to remove temporary hardness in water through Clark's process. It reacts with the soluble bicarbonates to precipitate them as insoluble carbonates, which are then easily removed by filtration.
Calcium hydroxide, commonly known as slaked lime, is used to remove temporary hardness in water through Clark's process. It reacts with the soluble bicarbonates to precipitate them as insoluble carbonates, which are then easily removed by filtration.
Think of it like adding a 'magnet' to a murky liquid that binds to unwanted floating debris, turning them into heavy solids that sink to the bottom so you can pour out the clear water.
CL-ark: Ca(OH)2 Lime
Ca(HCO3тАЛ)2тАЛ+Ca(OH)2тАЛтЖТ2CaCO3тАЛтЖУ+2H2тАЛO тАФ Chemical reaction for removing temporary hardness via Clark's process
Temporary hardness is caused by the presence of calcium bicarbonate, Ca(HCO3тАЛ)2тАЛ, and magnesium bicarbonate in water. When calcium hydroxide is added, it reacts with calcium bicarbonate to form insoluble calcium carbonate, CaCO3тАЛ, and water. The insoluble CaCO3тАЛ settles down and is removed, effectively softening the water.
Temporary hardness is due to bicarbonates of Calcium and Magnesium.
Clark's process is specifically used for large-scale treatment of temporary hardness.
Boiling is another simple method to remove temporary hardness by decomposing bicarbonates.
Cost-effective for large-scale water treatment
Uses readily available industrial chemicals
Requires precise dosage control to avoid leaving excess hydroxide
Not effective for permanent hardness
Municipal water treatment plants
Large-scale boiler feed water treatment
Permanent hardness is caused by chlorides and sulfates of Ca and Mg, which cannot be removed by boiling or lime.
Option A is the product formed after softening, not the agent. Option C is a common salt used in ion exchange (zeolite process) for permanent hardness. Option D is an oxidizing agent used for disinfection.
B is correct тАФ Calcium hydroxide reacts with soluble calcium bicarbonate to form insoluble calcium carbonate, facilitating the removal of temporary hardness.
Remember: Temporary hardness is due to bicarbonates (HCO3тИТтАЛ), while permanent hardness is due to chlorides (ClтИТ) and sulfates (SO42тИТтАЛ) of Ca/Mg.
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download тАв 100K+ Aspirants