Which of the following is NOT a characteristic of metals?
A. Ductility
B. High thermal conductivity
C. Malleability
D. Brittleness
Answer: Option D
Solution (By JKSSB Mock Tests)
Brittleness is a property typical of non-metals and metalloids; metals are ductile and malleable, not brittle. Ductility: drawn into wires (gold most ductile). Malleability: beaten into sheets (gold most malleable). Metals also have luster, high thermal and electrical conductivity, and sonorous nature. Brittle substances break easily under stress without significant deformation (e.g., glass, sulfur). Some metals like cast iron are brittle but generally pure metals are not.
Explanation:
Saponification is the hydrolysis of triglycerides (fats/oils) with NaOH or KOH to produce glycerol and the sodium or potassium salts of long-chain fatty acids, which are soaps. Esterification is the formation of esters from acid and alcohol. Emulsification is the dispersion of one liquid in another. Hydrogenation is addition of H₂. Hard soaps use NaOH, soft soaps use KOH. Soaps clean by micelle formation.
Explanation:
NH₃ has a lone pair on nitrogen; it donates this pair to H⁺ to form a coordinate (dative) bond, where both electrons in the bond come from nitrogen. The resulting NH₄⁺ has four equivalent N-H bonds.
Explanation:
Graphite slows down fast neutrons in nuclear reactors, enabling sustained chain reaction. Diamond is hard and insulating; fullerenes are nanomaterials; charcoal is adsorbent.
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