C. Changes the equilibrium constant of a reaction.
D. Alters the rate of a chemical reaction without being consumed.
Answer: Option D
Solution (By JKSSB Mock Tests)
A catalyst speeds up (positive catalyst) or slows down (negative catalyst) a chemical reaction by providing an alternative pathway with a lower (or higher) activation energy. It remains chemically unchanged and in the same amount at the end of the reaction, and does not alter the equilibrium position.
Explanation:
Nickel (finely divided) is used as a catalyst in the hydrogenation of unsaturated vegetable oils to saturated fats (vanaspati ghee). The reaction adds H₂ across double bonds. Platinum and palladium are also hydrogenation catalysts but nickel is cheaper and industrially preferred. Fe is used in Haber process for ammonia synthesis, V₂O₅ in contact process for H₂SO₄. Catalysts provide an alternative pathway with lower activation energy.
Explanation:
Light catalyzes decomposition of H₂O₂. Dark bottles (amber) block light, stabilizing it. Often a stabilizer like urea or phosphoric acid is added. Metal containers may catalyze decomposition.
Explanation:
Joseph Proust proposed the law of definite proportions (constant composition) – a given compound always contains the same elements in the same proportion by mass. Dalton's theory explained it. Lavoisier gave law of conservation of mass. Rutherford discovered nucleus.
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