Q5 / 160 · AP EAMCET 2006 · Chemistry

Which of the following is not correct?

  • Correct answer
    A
    $3 \mathrm{O}_2 \underset{\text { discharge }}{\stackrel{\text { silent electric }}{\rightleftarrows}} 2 \mathrm{O}_3 ; \Delta H=-284.5 \mathrm{~kJ}$
  • B
    Ozone undergoes addition reaction with unsaturated carbon compounds
  • C
    Sodium thiosulphate reacts with $\mathrm{I}_2$ to form sodium tetrathionate and sodium iodide.
  • D
    Ozone oxidises lead sulphide to lead sulphate.

Solution

The formation of ozone from oxygen is an endothermic reaction not exothermic reaction. $3 \mathrm{O}_2 \underset{\text { discharge }}{\stackrel{\text { Electric }}{\longrightarrow}} 2 \mathrm{O}_3 \quad \Delta H=287 \mathrm{~kJ}$ So, statement $3 \mathrm{O}_2 \underset{\text { discharge }}{\stackrel{\text { silent }}{\rightleftharpoons}} 2 \mathrm{O}_3 \quad \Delta H=-284.5 \mathrm{~kJ}$ is not correct statement.

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

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