Q21 / 170 · Manipal (MET) 2019 · Chemistry

Ozone when reacts with potassium iodide solution liberates certain product, which turns starch paper blue. The liberated substance is

  • A
    oxygen
  • Correct answer
    B
    iodine
  • C
    hydrogen iodide
  • D
    potassium hydroxide

Solution

$\mathrm{O}_3$ (Ozone) works as oxidising agent. It reacts with potassium iodide (KI) solution and liberate iodine vapours that turns starch paper blue. $\begin{aligned} \mathrm{O}_3 \longrightarrow & \mathrm{O}_2+\mathrm{O} \\ & \xrightarrow[2 \mathrm{KI}+\mathrm{H}_2 \mathrm{O}+\mathrm{O} \longrightarrow 2 \mathrm{KOH}+\mathrm{I}_2]{2 \mathrm{KI}+\mathrm{H}_2 \mathrm{O}+\mathrm{O}_3 \longrightarrow 2 \mathrm{KOH}+\mathrm{I}_2+\mathrm{O}_2}\end{aligned}$

Hence, the correct answer is option: 'B'.

More p Block Elements (Group 15, 16, 17 & 18) Questions