Principle

The organic dye crystal violet is decolorised in an alkaline medium. This reaction takes place according to a velocity-time law, hence it is a reaction of the first order.
Using the integrated software, the change in concentration of the dye can be traced by measuring the extinction at the wavelength of the absorption maximum. The computer program plots the kinetic data in graphical form.

Benefits

• Modern, easy-to-use photospectrometer
• Simple evaluation by integrated software

Tasks

The order of reaction during decolorisation of crystal violet is to be determined.

Learning objectives

• Reaction kinetics
• First order reaction
• Photometry
• Reaction rate

Necessary accessories

• Precision balance 620g/0.001g