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When phosphoric acid is added to hydrogen peroxide, it slows the decomposition of H₂O₂. Phosphoric acid acts as a:
A{'text': 'Positive catalyst'}
B{'text': 'Reactant in the reaction'}
C{'text': 'Inert solvent for water'}
D{'text': 'Negative catalyst'}
Answer & Solution
Correct answer: D. {'text': 'Negative catalyst'}
1. Hydrogen peroxide naturally decomposes to water and oxygen.
2. Phosphoric acid slows this rate without itself being consumed.
3. A catalyst that **slows** a reaction is called a **negative catalyst** (inhibitor).
4. It is not a reactant because it is not transformed in the equation.
5. Hence phosphoric acid here is a **negative catalyst**.
_Source: Selina Concise ICSE Class 8 Chemistry Ch 6 "Chemical Reactions", Catalysts classification_
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