Assertion (A): Silver and gold occur in the free state in nature. Reason (R): They are highly reactive metals.
A. Both A and R are true and R is the correct explanation of A.
B. A is false but R is true.
C. Both A and R are true but R is NOT the correct explanation of A.
D. A is true but R is false.
Answer: Option D
Solution (By JKSSB Mock Tests)
Silver and gold are noble metals and occur in the free (native) state in nature because they are extremely unreactive (least reactive), not highly reactive. They do not readily combine with oxygen, moisture, or acids. Thus, A is true, but R is false.
Explanation:
Chlorine forms hypochlorous acid (HOCl) which is a strong oxidizing agent that destroys bacteria and viruses. It does not remove particles (filtration does) or dissolved salts.
Explanation:
Thermite process uses a mixture of aluminium powder and iron(III) oxide: Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + heat. The reaction is highly exothermic, producing molten iron that is used to join railway tracks. Aluminium acts as a reducing agent. Copper, zinc, iron are not used as the reducing agent in this process.
Explanation:
Fractional distillation is specifically designed to separate miscible liquids whose boiling points differ by less than 25 K. It uses a fractionating column which provides surfaces for repeated evaporation and condensation, enriching the vapor with the more volatile component before it reaches the condenser.
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