Question

Which statement is false in case of equilibrium state? (1) There is no apparent change in the properties with time. (2) It is dynamic in nature since both forward and backward reactions occur at all times with same speed. (3) It can be attained from either side of the reaction. (4) It does not change with temperature.

Short answer

Statement (4) is false.

Step-by-step solution

- Understand equilibrium state

In a chemical equilibrium, the rate of the forward reaction equals the rate of the backward reaction, making the quantities of reactants and products constant over time.

- Analyze each statement

Evaluate if each statement aligns with the definition of equilibrium: (1) Properties remain unchanged over time, (2) Both reactions occur at the same speed, (3) Equilibrium can be approached from either side, (4) Temperature affects equilibrium position.

- Verify statement (1)

At equilibrium, there is no apparent change in the properties with time. This is true as no net change is observed.

- Verify statement (2)

Equilibrium is dynamic in nature, where forward and backward reactions occur continuously with the same speed. This is true.

- Verify statement (3)

Equilibrium can be attained whether starting from reactants or products. This is true as the system will reach the same equilibrium state.

- Verify statement (4)

Equilibrium does change with temperature as it can shift the balance of the forward and backward reactions. This is false.

- Conclusion

Based on the analysis, statement (4) 'Equilibrium does not change with temperature' is false.

Key concepts

Equilibrium State

In chemistry, an equilibrium state occurs when a chemical reaction proceeds at the same rate in both the forward and backward directions. This results in no net change in the concentrations of reactants and products over time. At this point, the system is in a balanced state and the proportions of substances involved remain constant. Even though the reactants and products are still moving, their amounts do not change noticeably. This characteristic balance is vital in understanding many chemical processes and reactions. It shows how dynamic processes might appear static at the macroscopic level, while still ongoing at the microscopic level.

Dynamic Equilibrium

An equilibrium state is always dynamic in nature. Dynamic equilibrium means that even though there is no observable change in the quantities of reactants and products, the forward and backward reactions are still occurring. These reactions happen at equal rates, hence canceling each other out. To visualize this, imagine a seesaw perfectly balanced in the middle. Both sides move up and down but neither side stays permanently down or up, maintaining balance. The forward reaction (convert reactants to products) and backward reaction (convert products to reactants) keeps happening incessantly without causing any overall change.

Temperature Effects on Equilibrium

Temperature plays a crucial role in chemical equilibrium. According to Le Chatelier's Principle, if the temperature of an equilibrium system is altered, the system will adjust to counteract that change. For instance, if you increase the temperature of a system where the forward reaction absorbs heat (endothermic reaction), the system will shift the equilibrium to favor the forward reaction to absorb the added heat. Conversely, for an exothermic reaction (releases heat), increasing the temperature will shift the equilibrium towards the backward reaction. This shows that equilibrium positions are indeed sensitive to temperature changes, disproving the idea that equilibrium is unaffected by temperature.

Reaction Rates

The concept of reaction rates is fundamental to understanding chemical equilibrium. The rate of a chemical reaction is the speed at which reactants convert to products. At equilibrium, the rates of the forward and backward reactions are equal. However, numerous factors can influence these rates, including temperature, concentration, and presence of catalysts. Higher temperatures typically increase reaction rates by providing reactant particles with more energy, which results in more effective collisions. Catalysts, on the other hand, speed up both forward and backward reactions without being consumed, helping the system reach equilibrium more swiftly but not affecting the equilibrium position. Understanding reaction rates is essential for predicting how changes in conditions will affect a reaction's progress and equilibrium state.