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WBJEE · Chemistry · Some Basic Concepts of Chemistry

\(1 \mathrm{~mL}\) of water has 25 drops. Let \(\mathrm{N}_0\) be the Avogadro number. What is the number of molecules present in 1 drop of water ? (Density of water \(=1 \mathrm{~g} / \mathrm{mL}\) )

  1. A \(\frac{0.02}{9} \mathrm{~N}_0\)
  2. B \(\frac{18}{25} \mathrm{~N}_0\)
  3. C \(\frac{25}{18} \mathrm{~N}_0\)
  4. D \(\frac{0.04}{25} \mathrm{~N}_0\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\frac{0.02}{9} \mathrm{~N}_0\)

Step-by-step Solution

Detailed explanation

Volume of one drop \(=\left(\frac{1}{25}\right) \mathrm{mL}\) \(\therefore\) Mass of \(1 \mathrm{drop}=\mathrm{V} \times \mathrm{d}\) \(=\left(\frac{1}{25} \mathrm{~mL}\right)(1 \mathrm{~g} / \mathrm{mL})\) \(=\frac{1}{25} \mathrm{~g}\) Number of moles of…