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During photosynthesis, plants use sunlight to convert CO₂ and water into glucose. This shows that light can:
A{'text': 'Only heat the reactants without combining them'}
B{'text': 'Always slow down chemical reactions'}
C{'text': 'Replace water as a reactant in any reaction'}
D{'text': 'Provide the energy a chemical reaction needs'}
Answer & Solution
Correct answer: D. {'text': 'Provide the energy a chemical reaction needs'}
1. Photosynthesis: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂.
2. The reaction does not proceed in darkness because light energy is needed to break and rearrange bonds.
3. So light is supplying the **energy a chemical reaction needs** — a photochemical reaction.
4. Light can drive reactions, not slow them as a rule; it cannot replace a chemical reactant.
_Source: Selina Concise ICSE Class 8 Chemistry Ch 6 "Chemical Reactions", Factors affecting reaction rates_
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