The molarity of \(0.2 \mathrm{~N} \mathrm{Na}_2 \mathrm{CO}_3\) solution will be

The molarity of \(0.2 \mathrm{~N} \mathrm{Na}_2 \mathrm{CO}_3\) solution will be
  1. \(0.05 \mathrm{M}\)
  2. \(0.2 \mathrm{M}\)
  3. \(0.1 \mathrm{M}\)
  4. \(0.4 \mathrm{M}\)

Solution

\(n\) - factor for \(\mathrm{Na}_2 \mathrm{CO}_3=2\) \(\therefore\) The \(n\)-factor of such salts is defined as the number of moles of electrons exchanged (lost or gained) by one mole of the salt and there is the exchange of 2 electrons, so its \(n\)-factor is 2. Therefore, normality \(=n\)-factor \(\times\) molarity \(\Rightarrow\) Molarity \(=0.2 / 2=0.1 \mathrm{M}\) Hence, the correct option is (c).

Asked in: AP EAMCET 2020 (21 Sep Shift 1)

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