Which of the following is an example of a redox reaction?
A. CaO + H₂O → Ca(OH)₂
B. NaCl + AgNO₃ → AgCl + NaNO₃
C. NH₃ + HCl → NH₄Cl
D. Zn + 2HCl → ZnCl₂ + H₂
Answer: Option D
Solution (By JKExamLibrary)
In Zn + 2HCl, Zn is oxidized (0 to +2) and H⁺ is reduced (+1 to 0). So it is a redox reaction. The other reactions are double displacement (A), combination without oxidation state change (B, D). Redox requires change in oxidation states.
Explanation:
Glass is an amorphous (non-crystalline) solid; it lacks a long-range ordered structure. It is sometimes called a supercooled liquid. It softens over a temperature range rather than having a sharp melting point. Quartz (SiO₂) is crystalline.
Explanation:
Carbon monoxide (CO) has a triple bond. In the formation, oxygen, with two lone pairs, donates one lone pair to form a coordinate bond with carbon after normal double bond formation, resulting in a structure :C≡O:. Thus oxygen donates the pair. This satisfies the octet for both.
Explanation:
Silver has the highest thermal conductivity, followed by copper. It's also the best electrical conductor. Copper is more commonly used due to cost.
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