Question

Which of the following conclusions concerning the concentration-time plot provided below is/are correct?

1. The concentration of substance D is decreasing over time.
2. The instantaneous reaction rate at point A is greater than the instantaneous reaction rate at point B.
3. Substance D is a product of the reaction.

Answer 1

1. Correct.

2. Insufficient information.

3. Insufficient information.

Step-by-step explanation:

The concentration of substance D is decreasing over time as indicated by the downward trend in the concentration-time plot. This is evident in the decreasing values on the y-axis, signifying a reduction in the concentration of substance D as the reaction progresses.

However, it is not possible to determine the instantaneous reaction rates at points A and B without additional information such as the slope of the concentration-time plot at these specific points. The instantaneous reaction rate is given by the slope of the tangent to the curve at a particular point. Without this slope information, we cannot conclude whether the rate at point A is greater than that at point B.

Similarly, it cannot be conclusively determined whether substance D is a product of the reaction based solely on the concentration-time plot. Additional data, such as the reactants involved and their corresponding concentration-time plots, would be necessary to make a definitive statement about the nature of substance D in the reaction.

In summary, while the decreasing concentration of substance D is evident, further information is needed to determine the relative instantaneous reaction rates at points A and B, as well as to ascertain whether substance D is indeed a product of the reaction.

Full Question:

Which of the following conclusions concerning the concentration-time plot provided below is/are correct?

1. The concentration of substance D is decreasing over time.

2. The instantaneous reaction rate at point A is greater than the instantaneous reaction rate at point B.

3. Substance D is a product of the reaction.

Answer 2

1. The concentration of substance D is decreasing over time.

2. The instantaneous reaction rate at point A is greater than the instantaneous reaction rate at point B.

3. Substance D is a product of the reaction.

Step-by-step explanation:

The concentration-time plot indicates that the concentration of substance D is indeed decreasing over time. This is evident from the downward slope of the curve representing substance D. As time progresses, the concentration of D decreases, suggesting its consumption in the reaction. This aligns with the typical behavior of a reactant during a chemical reaction.

To address the second point, we can analyze the slope of the concentration-time curve at points A and B. The slope of the curve at any point represents the instantaneous reaction rate. If the slope at point A is steeper than at point B, it implies a higher instantaneous reaction rate at A. Therefore, the statement that the instantaneous reaction rate at point A is greater than at point B is correct, provided the time axis is appropriately scaled.

Regarding the third point, the plot alone does not provide conclusive evidence about whether substance D is a product or a reactant. The decreasing concentration could indicate consumption as a reactant or formation as a product. Additional information about the reactants and products involved in the reaction is necessary to make a definitive conclusion about the role of substance D in the reaction.