FACTORS AFFECTING RATE OF REACTION:
The rate of a chemical reaction, which measures how quickly reactants are consumed or products are formed, is influenced by several factors. Here are the key factors affecting the rate of a reaction:
- Concentration: The concentration of reactants affects the rate of a reaction. Generally, an increase in reactant concentration leads to an increase in the reaction rate.
- Temperature: The rate of reaction increases with the increase in temperature. In most cases, the rate constant nearly doubles for a 10° rise in temperature.
- Pressure (for gases): In the case of gaseous reactants, pressure can influence the reaction rate.
- Catalysts: Catalysts are substances that accelerate a reaction by providing an alternative reaction pathway with lower activation energy. They increase the rate of reaction without being consumed in the process.
The rate of a chemical reaction depends upon:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → All of the above
The passage states that the rate of a reaction is affected by the concentration of the reactants, the temperature, the pressure (for gaseous reactants) and a catalyst.
For a gas, pressure acts through concentration: a higher pressure means more gas molecules in the same volume.
All three factors change the rate, so the answer is all of the above.
Why the other options are incorrect
Option (1) Pressure (for gaseous reactants) — Incorrect. Pressure is a factor, but not the only one; temperature and concentration also change the rate.
Option (2) Temperature — Incorrect. The rate rises with temperature, but it also depends on the concentration (pressure for gases).
Option (3) Concentration of the reactants — Incorrect. Concentration is a factor, but temperature also changes the rate.