Fuel

  • M/J 2018/P12/Q18

The equation for photosynthesis is shown.

6CO2 + 6H2O → 6O2 + C6H12O6

Which statement about photosynthesis is correct?

​​ A​​ ​​ It has a negative enthalpy change.

​​ B ​​​​ It is catalyzed by the presence of yeast.

​​ C​​ ​​ The products of photosynthesis are oxygen and starch.

​​ D​​ ​​ It occurs in green leaves.

 ​​ ​​ ​​ ​​ ​​​​ 

Answer: ​​ D

Explaination

Green leaves contain green color pigment called  ​​ ​​ ​​ ​​ ​​ ​​ ​​​​ chlorophyll which is responsible for photosynthesis in the presence of sunlight. Green leaves take CO2​​ and H20 from the environment and convert them into simple glucose molecule C6H12O6​​ and oxygen. Starch is a polysaccharide carbohydrate not a glucose molecule. As photosynthesis is an endothermic reaction, it absorbs heat from sunlight and sign of enthalpy is +ve for endothermic reaction. Sunlight and chlorophyll act as a catalyst help the reaction to become faster.​​