Question

The rate of reaction for the reaction between ionic compounds cannot be determined because they are generally:

• A. immeasurably slow reactions
• B. moderately slow reactions
• C. instantaneous reactions
• D. not precipitation reactions

Answer 1

Answer: (C)

instantaneous reactions

Ionic reactions are instantaneous thus their rate of reaction can not be determined. The instantaneous rate of reaction is defined as the change in concentration of an infinitely small time interval, expressed as the limit or derivative expression above. Instantaneous rate can be obtained from the experimental data by first graphing the concentration of a system as function of time, and then finding the slope of the tangent line at a specific point which corresponds to a time of interest. Alternatively, experimenters can measure the change in concentration over a very small time period two or more times to get an average rate close to that of the instantaneous rate. The reaction rate for that time is determined from the slope of the tangent lines.