Temporary hardness of water is caused by bicarbonates. Boiling removes it by converting bicarbonates to:
A. Insoluble carbonates
B. Sulfates
C. Nitrates
D. Chlorides
Answer: Option A
Solution (By JKExamLibrary)
Ca(HCO₃)₂ → CaCO₃↓ + H₂O + CO₂ (on boiling). The precipitate is calcium carbonate. Sulfates and chlorides cause permanent hardness and cannot be removed by boiling.
Explanation:
Biofertilizers are living microorganisms that enrich the soil quality. Rhizobium is a symbiotic bacterium found in the root nodules of leguminous plants that fixes atmospheric nitrogen. Urea, NPK, and ammonium sulfate are chemical fertilizers synthesized through industrial processes.
Explanation:
Temporary hardness is due to Ca(HCO₃)₂ and Mg(HCO₃)₂. Upon boiling, these decompose into insoluble CaCO₃ and Mg(OH)₂, which precipitate out and can be filtered. Thus, boiling effectively removes temporary hardness, and R correctly explains the chemical mechanism involved.
Explanation:
Mass number (A) = number of protons (Z) + number of neutrons (N). Electrons have negligible mass and are not counted. It is the total number of nucleons. Example: ¹²C has 6 protons + 6 neutrons = 12. Isotopes have same Z but different A due to varying N. Atomic mass (weight) is the weighted average.
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