The question asks to identify which statement is NOT a characteristic of a system at physical equilibrium. We need to recall the definition and properties of physical equilibrium to evaluate each option.
Correct Option: C) Measurable properties of the system change continuously
This statement is incorrect because, at physical equilibrium, all measurable (macroscopic) properties of the system remain constant over time. If they were continuously changing, the system would not be in equilibrium but rather undergoing a process towards equilibrium or another state.
The question asks how to confirm the dynamic nature of equilibrium in a saturated sugar solution. Dynamic equilibrium implies that forward and reverse processes are occurring at equal rates, even though there is no net change in the macroscopic properties of the system. To confirm this, we need a method that can detect the ongoing exchange of molecules between the dissolved and undissolved states.
D) Radioactive sugar molecules — By using radioactive sugar molecules, we can trace the movement of sugar from the solid phase to the dissolved phase (and vice versa) even when the system is at equilibrium and there is no net change in concentration. If radioactive sugar is added to the solid phase, its presence in the solution over time, while the solution remains saturated, confirms that sugar molecules are continuously dissolving and crystallizing, demonstrating the dynamic nature of the equilibrium.
This question tests the understanding of equilibrium in a saturated solution. A saturated solution is one where the maximum amount of solute has been dissolved in a solvent at a given temperature. At this point, the system reaches a dynamic equilibrium.
Correct Option: A) Rate of dissolution equals rate of crystallization. This accurately describes the state of dynamic equilibrium in a saturated solution, where opposing processes occur at equal rates, leading to no net change.
The question asks about the characteristics of a system at chemical equilibrium. Understanding the dynamic nature of equilibrium is key to identifying the correct statement.
B) Concentrations of reactants and products remain constant. This is the defining characteristic of chemical equilibrium. While the reactions continue, the net change in concentrations is zero because the rate of formation of products equals the rate of their consumption, and vice-versa for reactants.
The Haber's process is a well-known industrial method for synthesizing ammonia from nitrogen and hydrogen. The key to identifying the correct representation is to ensure the chemical equation is balanced according to the law of conservation of mass, meaning the number of atoms of each element must be the same on both sides of the reaction.
Correct Option: D) N₂(g) + 3H₂(g) ⇌ 2NH₃(g) is the correctly balanced chemical equation for the synthesis of ammonia in the Haber's process.
The question asks what the use of deuterium (\(\text{D}_2\)) instead of hydrogen (\(\text{H}_2\)) in ammonia synthesis demonstrates. This relates to the concept of chemical equilibrium and how isotopic substitution can be used to study reaction mechanisms.
Correct Option: C) Chemical equilibrium is dynamic with continuous forward and reverse reactions. The isotopic exchange observed when \(\text{D}_2\) is used in the Haber process (and then \(\text{H}_2\) is introduced) is a classic demonstration that even at equilibrium, reactions are still proceeding in both directions, but at equal rates.