Find the correct combination about the following plots (P,Q and R) for the variation rate of reaction with time.
Find the correct combination about the following plots (P,Q and R) for the variation rate of reaction with time.
Q=Reversible;P=Zero order;R=Irreversible
R=Zero order;P=Zero order;R=Irreversible
Q=Irreversible;R=Reversible;P=Zero order
P=Irreversible;Q=Reversible;R=Zero order
P=Reversible;Q=Zero order;R=Irreversible
The Correct Option is D
Approach Solution - 1
Plot (P): The rate decreases over time, but it's not a constant rate. The rate starts high and gradually decreases, approaching zero. This suggests a reaction where the rate depends on the concentration of reactants, and as reactants are consumed, the rate slows down. This is characteristic of a first or higher order reaction, not zero-order. Further, there is no reverse reaction so it is irreversible
Plot (Q): This plot clearly shows both forward and backward reaction rates. The rates converge to a point where the forward and backward rates are equal, indicating equilibrium. This is a reversible reaction. It is not zero order, since it is not linear.
Plot (R): The rate is constant until some of it disappears, then remains constant.
This is an odd reaction, but fits the graph for a zero order reaction.
Therefore, the correct combination is (D) P = Irreversible; Q = Reversible; R = Zero order
Approach Solution -2
Let's analyze the given plots (P, Q, and R) for the variation rate of reaction with time to find the correct combination.
Plot P
- The rate of reaction decreases exponentially with time.
- This suggests that the concentration of reactants is decreasing over time, which is typical for an irreversible reaction.
- Conclusion: Plot P corresponds to an irreversible reaction.
Plot Q
- There are two curves: one decreasing and one increasing, which eventually reach equilibrium.
- This indicates that initially, the forward reaction rate is higher and the backward reaction rate is lower. Over time, they become equal.
- This is characteristic of a reversible reaction where the forward and backward reaction rates eventually reach equilibrium.
- Conclusion: Plot Q corresponds to a reversible reaction.
Plot R
- The rate of reaction remains constant over time.
- This is indicative of a zero-order reaction, where the rate is independent of the concentration of reactants.
- Conclusion: Plot R corresponds to a zero-order reaction.
Correct Combination
- P: Irreversible reaction
- Q: Reversible reaction
- R: Zero-order reaction
Hence, the correct combination is:
\[\boxed{P = \text{Irreversible}; Q = \text{Reversible}; R = \text{Zero order}}\]
So the correct Answer is Option 4(D): P=Irreversible;Q=Reversible;R=Zero order
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Concepts Used:
Rate of a Chemical Reaction
The rate of a chemical reaction is defined as the change in concentration of any one of the reactants or products per unit time.
Consider the reaction A → B,
Rate of the reaction is given by,
Rate = −d[A]/ dt=+d[B]/ dt
Where, [A] → concentration of reactant A
[B] → concentration of product B
(-) A negative sign indicates a decrease in the concentration of A with time.
(+) A positive sign indicates an increase in the concentration of B with time.
Factors Determining the Rate of a Reaction:
There are certain factors that determine the rate of a reaction:
- Temperature
- Catalyst
- Reactant Concentration
- Chemical nature of Reactant
- Reactant Subdivision rate