Water is said to be permanently hard when it contains:
Correct answer: D. chlorides of Ca2+ and Mg2+ ions
- A. carbonates of Ca2+ and Mg2+ ions
- B. Bicarbonates of Ca2+ and Mg2+ ions
- C. sulphates of Na+ and Mg2+ ions
- D. chlorides of Ca2+ and Mg2+ ions
Explanation
The presence of soluble salts of calcium and magnesium, i.e., sulfates and chlorides of calcium and magnesium, causes permanent hardness in the water.
Last updated
About Water Pollution and Treatment
Water pollution covers biological, chemical and physical contaminants, including pathogens, toxic metals, detergents and excess nutrients. Treatment involves screening, sedimentation, coagulation, filtration, disinfection and wastewater processing, while biochemical oxygen demand, chemical oxygen demand, eutrophication and dissolved oxygen indicate pollution levels.
Practise Environmental Chemistry
221 free Environmental Chemistry MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Chemistry questions like this
Chemistry is on 12 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
Identify which one of the following water pollutant is Carcinogenic?
The disadvantage of use of chlorinated water is:
The coagulant used in raw water to precipitate suspended impurities is:
What is the most important source of water pollution in Pakistan?
Commonly used coagulant used for the purification of water is: