Question

The correct equation for photosynthesis is
a) \[{{\text{C}}_{6}}{{\text{H}}_{12}}{{\text{O}}_{6}}\text{ + 6}{{\text{O}}_{2}}\text{ }\to \text{ 6C}{{\text{O}}_{2}}\text{ + 6}{{\text{H}}_{2}}\text{O}\]
b) \[\text{6C}{{\text{O}}_{2}}\text{ + 6}{{\text{H}}_{2}}\text{O}\ \text{ }\to \text{ }{{\text{C}}_{6}}\text{ + }{{\text{H}}_{12}}{{\text{O}}_{6}}\text{ + 6}{{\text{O}}_{2}}\]
c) \[\text{6C}{{\text{O}}_{2}}\text{ }+12{{\text{H}}_{2}}\text{O }\to {{\text{C}}_{6}}{{\text{H}}_{12}}{{\text{O}}_{6}}\text{ + 6}{{\text{O}}_{2}}\text{ + 6}{{\text{H}}_{2}}\text{O}\]
d) \[\text{6C}{{\text{O}}_{2}}\text{ + 10}{{\text{H}}_{2}}\text{O }\to \text{ }{{\text{C}}_{6}}{{\text{H}}_{12}}{{\text{O}}_{6}}\text{ + }{{\text{O}}_{2}}\text{ + 4}{{\text{H}}_{2}}\text{O}\]

Answer 1

Hint: Photosynthesis is the process by which plants synthesize their own food material i.e. carbohydrates by using carbon dioxide and water from the soil. Sunlight is essential for this process.

Complete answer:
The word ‘photo’ means light and ‘synthesis’ means production i.e. combining with the help of light. It occurs in chloroplasts which are present in all the green parts of a plant including stem, green leaves and sepals. Two reactants i.e. carbon dioxide and water are involved in photosynthesis reaction and products formed are two i.e. glucose and oxygen. Overall, photosynthesis is an endothermic reaction which has following reaction –
\[\text{6C}{{\text{O}}_{2}}\text{ }+12{{\text{H}}_{2}}\text{O }\to {{\text{C}}_{6}}{{\text{H}}_{12}}{{\text{O}}_{6}}\text{ + 6}{{\text{O}}_{2}}\text{ + 6}{{\text{H}}_{2}}\text{O}\]

Additional information:
Various factors such as intensity of light, temperature, concentration of carbon dioxide, water levels and pollution have considerable effects on the rate of photosynthesis and thus production of carbohydrates. If intensity of light increases, the rate of photosynthesis also increases and vice versa. Similarly the rate of photosynthesis increases with increase in the concentration of water and carbon dioxide. Generally, 300-400 PPM of carbon dioxide is sufficient for photosynthesis to occur. Photosynthesis occurs most efficiently at \[{\text{2}}{{\text{5}}^o}{\text{C to 3}}{{\text{5}}^o}{\text{C}}\]. Further, the process of photosynthesis is completed in two stages – first is called ‘light dependent reactions’ and the second is ‘light independent or dark reaction’.

So, the correct answer is \[\text{6C}{{\text{O}}_{2}}\text{ }+12{{\text{H}}_{2}}\text{O }\to {{\text{C}}_{6}}{{\text{H}}_{12}}{{\text{O}}_{6}}\text{ + 6}{{\text{O}}_{2}}\text{ + 6}{{\text{H}}_{2}}\text{O}\]

Note:
Due to extreme levels of pollution, particulate forms of pollutants settle on the surface of the leaves thus blocking the sunlight from entering into them and hence also has adverse effects on the rate of photosynthesis.