4) The reaction below takes place until the solution went from yellow to clear. If iodine...

4) The reaction below takes place until the solution went from yellow to clear. If iodine was the contributor to the yellow color, how many moles of I2(aq) are present after completion? Explain your answer. (2 pts) CH3COCH3(aq) + I2(aq) à CH3COCH2I(aq) + H+ (aq) + I- (aq)

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Expert Solution

As the following reaction proceeds,

CH3COCH3(aq) + I2(aq) --------> CH3COCH2I(aq) + H+(aq) + I - (aq)

colourless (brown/yellow) colourless colourless

The concentration of iodine decreases and the brown/yellow colour intensity of the reacting solution also decreases. The change in colour intensity allows the use of colorimetry to follow the reaction kinetics. For dilute solutions, absorbance is proportional to concentration. Decrease in concentration of species can be measured by the change in absorbance. Relative rate of disappearance of iodine, in terms of decrease in absorbance and not in terms of actual decrease in concentration of iodine, is measured from the absorbance vs time plot. This avoids the time-consuming conversion to concentration units using a calibration curve. Order of reaction with respect to each reactant is determined by separately doubling the concentrations of each of CH3COCH3(aq), H+(aq) and I2(aq). A first order reaction with respect to CH3COCH3(aq) is confirmed when, while keeping the concentrations of I2(aq) and H+(aq) constant, the initial rate of decrease in concentration of I2(aq) (or the initial rate of decrease in absorbance) doubles as the concentration of CH3COCH3(aq) is doubled. Hence rate of reaction with respect to I2 is zero.The no of moles of I2 decreased will be directly equal to the moles of increase in CH3COCH3..This decrease subracted from initial I2 moles give your answer.This is to be performed in colorimeter.It should be solved experimentally with data.

If data is provided we can solve it.

queen_honey_blossom answered 1 year ago

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