The term `(-(dc)/(dt))` in a rate equation refers to the :

Options

A. Concentration of the reactant
B. Decrease in concentration of the reactant with time
C. Increase in concentration of the reactant with time
D. Velocity constant of the reaction

Answer

To solve the question regarding the term `(-(dc)/(dt))` in a rate equation, let's break it down step by step:

### Step 1: Understand the Rate Equation
The rate of a chemical reaction can be expressed in terms of the change in concentration of reactants and products over time. The general form of a rate equation for a reaction can be written as:

\[ \text{Rate} = -\frac{d[A]}{dt} = \frac{d[B]}{dt} \]

where \([A]\) is the concentration of the reactant and \([B]\) is the concentration of the product.

### Step 2: Identify the Meaning of `-(dc)/(dt)`
In the given term `-(dc)/(dt)`, we can interpret this as follows:
- The `c` represents the concentration of a reactant (let's assume it is the concentration of A).
- The `d` indicates a differential change, and `t` represents time.
- The negative sign indicates that as time progresses, the concentration of the reactant is decreasing.

### Step 3: Relate to the Reaction
As the reaction proceeds, the concentration of the reactant decreases because it is being converted into products. Therefore, `-(dc)/(dt)` quantifies how fast the concentration of the reactant is decreasing over time.

### Step 4: Conclusion
Thus, `-(dc)/(dt)` represents the rate of disappearance of the reactant with respect to time. It indicates that the concentration of the reactant is decreasing as the reaction progresses.

### Final Answer
The term `-(dc)/(dt)` in a rate equation refers to the rate of disappearance of the reactant with respect to time.

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