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WBJEE · Chemistry · Classification of Elements and Periodicity in Properties

\(5.75 \mathrm{mg}\) of sodium vapour is converted to sodium ion. If the ionisation energy of sodium is \(490 \mathrm{~kJ} \mathrm{~mol}^{-1}\) and atomic weight is 23 units, the amount of energy needed for this conversion will be

  1. A \(1.96 \mathrm{~kJ}\)
  2. B \(1960 \mathrm{~kJ}\)
  3. C \(122.5 \mathrm{~kJ}\)
  4. D \(0.1225 \mathrm{~kJ}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(0.1225 \mathrm{~kJ}\)

Step-by-step Solution

Detailed explanation

\(\mathrm{Na}(\mathrm{g}) \longrightarrow \mathrm{Na}^{+}(\mathrm{g})+\mathrm{e}^{-}\) \(1 \mathrm{~mol} \mathrm{Na}(\mathrm{g})\) requires \(490 \mathrm{~kJ} /\) mol for ionization. \(\therefore \quad \frac{5.75 \times 10^{-3}}{23}\) mol \(\quad\) requires…