In the reaction represented above, the number of MnO_4^- ions that react must he
ID: 498618 • Letter: I
Question
In the reaction represented above, the number of MnO_4^- ions that react must he equal to which of the following? (A) One-fifth the number of Fe^2+ ions that are consumed (B) Eight times the number of H^+ ions that are consumed (C) Five times the number of Fe^3+ ions that are produced (D) One-half the number of H_2O molecules that are produced. A student prepared five solutions of CuSO_4 with different concentrations, and then filled five cuvettes, each containing one of the solutions. The cuvettes were placed in a spectrophotometer set to the appropriate wavelength for maximum absorbance. The absorbance of each solution was measured and recorded. The student plotted absorbance versus concentration, as shown in the figure above. Which of the following is the most likely explanation for the variance of the data point for the 0.600 M CuSO_4 solution? (A) The cuvette into which the 0.600 M solution was placed had some water droplets inside. (B) The cuvette into which the 0.600 M solution was placed was filled slightly more than the other cuvettes. (C) The wavelength selling was accidentally moved away from that of maximum absorbance. (D) The cuvette used for the 0.600 M solution had not been wiped clean before being put in the spectrophotometer.Explanation / Answer
26. one fifth the number of Fe^2+ ion that is consumed
27. D , the cuvette was not wiped clean. As a result , the actual concentration of solution is more than 0.6 M. Concentration is diretly proprtional to absorbance. So, solution has a greater absorbance value.