Q31 / 180 · JIPMER 2015 · Chemistry

Sodium sulphite is used in preserving squashes and other mildly acidic foods due to

  • A
    potassium salt has preservative action
  • B
    potassium metabisulphite prevents oxidation
  • C
    potassium metabisulphite is not influcenced by acid
  • Correct answer
    D
    sulphur dioxide and sulphurous acid formed kill bacteria and germs

Solution

$\begin{aligned} & \mathrm{K}_2 \mathrm{~S}_2 \mathrm{O}_5 \mathrm{~K}_2 \mathrm{SO}_3+\mathrm{SO}_2 \\ & \mathrm{SO}_2+\mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{H}_2 \mathrm{SO}_3\end{aligned}$ $\mathrm{SO}_2$ and sulphurous acid $\left(\mathrm{H}_2 \mathrm{SO}_3\right)$ kill the bacteria and prevent the decay of food.

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

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