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In a reaction, aA+bBrarrcC+dD rate =...

In a reaction,
`aA+bBrarrcC+dD`
rate `=-1/a(d[A])/(dt)` , the - ve sign in it represents

A

The rate of reaction increases with time

B

The rate is negative for the reaction

C

The concentration of the reactant 'A' decreases during the reaction

D

The concentration of reactant 'A' increases in the reaction

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding the negative sign in the rate expression for the reaction \( aA + bBr \rightarrow cC + dD \), we will analyze the meaning of the rate of reaction and the role of reactants and products. ### Step-by-Step Solution: 1. **Understanding the Rate Expression**: The rate of reaction is given by the expression: \[ \text{Rate} = -\frac{1}{a} \frac{d[A]}{dt} \] Here, \([A]\) represents the concentration of reactant A, and \(d[A]/dt\) is the change in concentration of A with respect to time. 2. **Significance of the Negative Sign**: The negative sign in the rate expression indicates that the concentration of reactant A is decreasing over time. In chemical reactions, reactants are consumed to form products. Therefore, as the reaction progresses, the concentration of A diminishes. 3. **Graphical Interpretation**: If we were to plot the concentration of A against time, we would observe a downward slope, indicating that the concentration of A is decreasing. The negative sign in the rate expression mathematically represents this decrease. 4. **Conclusion**: The negative sign is not an indication of the rate being negative or that the reaction is unfavorable; rather, it signifies that the concentration of the reactant A is decreasing as the reaction proceeds. Thus, the correct interpretation is that the concentration of reactant A decreases during the reaction. ### Final Answer: The negative sign in the rate expression represents that the concentration of reactant A decreases during the reaction. ---
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Knowledge Check

  • For a reaction A+3BrarrP , Rate = (-d[A])/(dt) ,the expression for the rate of reaction in terms of change in the concentration of B,(-d[B])/(dt) will be :

    A
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    A
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    B
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    C
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    D
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    A
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    C
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