In the froth flotation process, the depressant is used to:
A. Dissolve the ore.
B. Enhance the froth formation of all minerals.
C. Increase the density of the gangue.
D. Prevent one specific mineral from coming to the froth.
Answer: Option D
Solution (By JKSSB Mock Tests)
Froth flotation separates sulfide ores from gangue based on their wetting properties. Sometimes, an ore contains multiple sulfides. A depressant (like NaCN) is added to selectively prevent one mineral (e.g., FeS2) from attaching to the froth, allowing only the desired mineral (e.g., PbS) to be separated.
Explanation:
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:
Sodium acetate (CH₃COONa) is a salt of weak acid (acetic acid) and strong base (NaOH). It hydrolyzes to produce OH⁻ ions: CH₃COO⁻ + H₂O ⇌ CH₃COOH + OH⁻, making the solution basic. NaCl (strong acid-strong base) neutral. NH₄Cl (strong acid-weak base) acidic. NaNO₃ neutral. Basic salts turn red litmus blue.
Explanation:
A homogeneous mixture has uniform composition throughout. Salt completely dissolves in water, forming a single phase (solution). Oil and water are immiscible (heterogeneous). Sand in water is suspension (heterogeneous). Iron filings and sulfur can be heterogeneous unless alloyed.
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