Easy MCQ +4 / -1 PYQ · JEE Mains 2023

The normal rain water is slightly acidic and its $\mathrm{pH}$ value is $5.6$ because of which one of the following?

  1. A $\mathrm{N}_{2} \mathrm{O}_{5}+\mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{HNO}_{3}$
  2. B $2 \mathrm{SO}_{2}+\mathrm{O}_{2}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{H}_{2} \mathrm{SO}_{4}$
  3. C $4 \mathrm{NO}_{2}+\mathrm{O}_{2}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 4 \mathrm{HNO}_{3}$
  4. D $\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{H}_{2} \mathrm{CO}_{3}$ Correct answer

Solution

Normally rain water has a pH of 5.6 due to presence of H<sup>+</sup> ions formed by the reaction of rain water with carbon dioxide present in the atmosphere. <br/><br/>$$ \begin{aligned} & \mathrm{H}_2 \mathrm{O}(\mathrm{l})+\mathrm{CO}_2(\mathrm{~g}) \leftrightharpoons \mathrm{H}_2 \mathrm{CO}_3(\mathrm{aq}) \\\\ & \mathrm{H}_2 \mathrm{CO}_3(\mathrm{aq}) \leftrightharpoons \mathrm{H}^{+}(\mathrm{aq})+\mathrm{HCO}_3^{-}(\mathrm{aq}) \end{aligned} $$

About this question

Subject: Chemistry · Chapter: p-Block Elements · Topic: Group 13: Boron Family

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