Easy MCQ +4 / -1 PYQ · JEE Mains 2022

For kinetic study of the reaction of iodide ion with $\mathrm{H}_{2} \mathrm{O}_{2}$ at room temperature :

(A) Always use freshly prepared starch solution.

(B) Always keep the concentration of sodium thiosulphate solution less than that of KI solution.

(C) Record the time immediately after the appearance of blue colour.

(D) Record the time immediately before the appearance of blue colour.

(E) Always keep the concentration of sodium thiosulphate solution more than that of KI solution.

Choose the correct answer from the options given below :

  1. A $(\mathrm{A}),(\mathrm{B}),(\mathrm{C})$ only Correct answer
  2. B $(\mathrm{A}),(\mathrm{D}),(\mathrm{E})$ only
  3. C $(\mathrm{D}),(\mathrm{E})$ only
  4. D $(\mathrm{A}),(\mathrm{B}),(\mathrm{E})$ only

Solution

To minimize contamination, use freshly prepared starch solution to determine end point. As $\mathrm{KI}$ is used in excess to consume all the $\mathrm{H}_{2} \mathrm{O}_{2}$ the concentration of sodium thiosulphate solution is less than $\mathrm{KI}$ solution. After appearance of blue colour record the time immediately.

About this question

Subject: Chemistry · Chapter: Chemical Kinetics · Topic: Rate of Reaction

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