The role of a catalyst in a chemical reaction is to:
A. Increase the temperature of the reaction
B. Provide an alternative pathway with lower activation energy
C. Decrease the enthalpy change
D. Increase the equilibrium constant
Answer: Option B
Solution (By JKExamLibrary)
A catalyst lowers the activation energy (Ea) by providing an alternative reaction mechanism, thereby increasing the rate of both forward and reverse reactions equally. It does not affect the equilibrium constant, enthalpy change (ΔH), or the position of equilibrium. It remains chemically unchanged after reaction. Positive catalysts speed up, negative catalysts slow down. Enzymes are biological catalysts.
Explanation:
A negative catalyst (inhibitor) decreases the rate of a reaction by increasing activation energy or destroying active intermediates. Example: phosphoric acid inhibits H₂O₂ decomposition. Positive catalysts speed up, enzymes are biocatalysts, autocatalysts are products that catalyze their own formation.
Explanation:
From Faraday's first law, m = ZQ, so Z = m/Q. SI unit is kg/C, but practical unit is g/C. It is the mass of substance liberated per unit charge.
Explanation:
Both diamond and graphite are allotropes of carbon, having the same chemical element but different structural arrangements: diamond has a tetrahedral 3D network, graphite has layered planar structure. This leads to differing physical properties (hardness, conductivity).
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