Which indicator is most suitable for the titration of a weak acid with a strong base?
A. Methyl red
B. Phenolphthalein
C. Litmus
D. Methyl orange
Answer: Option B
Solution (By JKSSB Mock Tests)
In the titration of a weak acid with a strong base, the equivalence point occurs in the basic region (pH > 7) due to the hydrolysis of the conjugate base formed. Phenolphthalein changes color in the pH range of 8.2 to 10.0, making it the most suitable indicator for detecting this basic equivalence point.
Explanation:
The ozone layer is located in the lower stratosphere (~15-35 km altitude), where ozone concentration is highest. It absorbs harmful ultraviolet radiation (UV-B and UV-C) from the sun. Ground-level ozone (troposphere) is a pollutant and component of smog, harmful to health. Ozone depletion is caused by chlorofluorocarbons (CFCs) which release chlorine atoms that catalytically destroy O₃.
Explanation:
Ethanol is a versatile solvent used in medicines like tinctures and perfumes. Ethanoic acid (glacial) can act as a solvent for many organic compounds. Ethyl ethanoate is an excellent solvent for fats, resins, and plastics, often used in nail polish removers and industrial paints.
Explanation:
Green manure refers to crops (like sunn hemp or dhaincha) that are grown specifically to be plowed back into the soil while they are still green. This decomposing plant material enriches the soil with organic matter, nitrogen, and other nutrients, improving soil structure and fertility.
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