Chapter 7, Problem 7.10P

7-10 The rate of disappearance of HCI was measured for the following reaction:

The initial concentration of HCI is 1.85 M. Its concentration decreases to 1.58 M in 54.0 min. What is the rate of reaction?

Interpretation Introduction

Interpretation:

The rate of given reaction with initial concentration of $\text{HCl}$ 1.85M and decreased to 1.58 M in 54 min should be identified.

Concept introduction:

Rate of reaction: The rate of the reaction is defined as extent of a reaction. For any reaction, it depends on the concentration change of limiting reagent formed in a reaction.

Concentration: Concentration of all chemical species takes part in a reaction depend on their moles present in per liter solution.

The rate is change in concentration of the reactant with change in time. It is mathematically represented as follows:

  $\mathrm{Rate}=\frac{\mathrm{Final}\text{ concentration}-\text{initial concentration}}{\text{change in time}}$

Answer to Problem 7.10P

Rate of reaction = 0.005 M/min

Explanation of Solution

Given information:

Reaction with initial concentration of $\text{HCl}$ 1.85 M that decreased to 1.58 M in 54 min.

  $\mathrm{Rate}=\frac{\mathrm{Final}\text{ concentration}-\text{initial concentration}}{\text{change in time}}$

Put the given values in above expression.

$\text{Rate=}\frac{\text{1}\text{.58-1}\text{.85}}{\text{54}}\text{=}\frac{\text{-0}\text{.27}}{\text{54}}\text{= -0}\text{.005 M/min}$

Here, negative sign indicates the concentration of HCl decreases.

Conclusion

Rate of reaction = -0.005 M/min