The substance that increases the efficiency of a catalyst is called a:
A. Inhibitor
B. Promoter
C. Reactant
D. Poison
Answer: Option B
Solution (By JKExamLibrary)
A promoter is a substance that, when added in small quantities, enhances the activity or efficiency of a catalyst. For example, in the Haber process, molybdenum acts as a promoter for the iron catalyst. An inhibitor or poison decreases catalyst activity by blocking active sites.
Explanation:
In 2Na + Cl₂ → 2NaCl, sodium is oxidized (Na → Na⁺ + e⁻) and chlorine is reduced (Cl₂ + 2e⁻ → 2Cl⁻). It involves change in oxidation states. Options A and B are double displacement (no change in oxidation states). Option D is decomposition with no change in oxidation states (Ca: +2 remains +2). Redox reactions involve simultaneous oxidation and reduction.
Explanation:
BF3 has a trigonal planar geometry with bond angles of 120 degrees. The three B-F bond dipoles are equal in magnitude and symmetrically arranged, so their vector sum cancels out completely, resulting in a net dipole moment of zero. H2S is bent, NF3 is pyramidal, and ClF3 is T-shaped.
Explanation:
Portland cement primarily consists of calcium silicates (C₃S and C₂S) along with aluminates. These are formed by heating limestone and clay.
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