Question

In this lab we will investigate the bleaching of a dye by sodium hypochlorite. Bleaching is the processof converting the colored molecule into one that is colorless, usually through oxidation. The arrangement of double bonds in the Allura red molecule are said to be in conjugation. Removing one of the double bonds using oxidation properties of sodium hypochlorite destroys the molecules conjugation and ability to absorb light in the visible region.

The goal of this lab is to determine the rate law for the reaction between Allura Red and OCl-. Briefly describe, including temperature and concentration of the reactants, which reactions (individual experimental trials) you need to run to determine: i) the reaction order with respect to AR, ii) the reaction order with respect to OCl-, iii) the activation energy for this reaction.

Answer 1

To determine the order of reactions various experimental techniques are used like

1) integrated equation method

in integrated equation method for a reaction invloving single reactent the experimental values of a( intaial concentration ), x (Concentration at time t ) at a given time are meassured and values are subsituted in different integrated rate equations for different orders one by one . The equation which gives constant value for K suggest the order.

2) Fractional change method :

in this method order of reaction is calculated by the experssion

3. Van't Hoff differnential method

the activation energy can be calculated by