B. It has strong covalent network bonds throughout the crystal
C. It has weak bonds
D. It has free electrons
Answer: Option B
Solution (By JKExamLibrary)
Diamond is a giant covalent structure where each carbon is tetrahedrally bonded to four others via strong covalent bonds. Melting requires breaking numerous strong bonds, needing very high temperature (~3500°C). Graphite also has high melting point. Molecular solids like ice have low melting points. Carbon alone doesn't guarantee high m.p.; it's the structure.
Explanation:
Vitamin C is chemically known as ascorbic acid (C6H8O6). It is a vital nutrient involved in the repair of tissue and the enzymatic production of certain neurotransmitters. Deficiency leads to scurvy. Retinol is Vitamin A, Calciferol is Vitamin D, and Tocopherol is Vitamin E.
Explanation:
Ethanol (C₂H₅OH) on heating with excess concentrated H₂SO₄ (dehydrating agent) at 170°C undergoes dehydration to give ethene (C₂H₄). This is an elimination reaction. Oxidation gives ethanoic acid; hydrogenation adds H₂; fermentation produces ethanol.
Explanation:
Catalysts provide an alternative reaction pathway with lower activation energy, increasing the fraction of effective collisions. They are not consumed and do not alter the overall enthalpy change (ΔH) or equilibrium constant.
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