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JEE Main 201323 AprilOnline

Exam: JEE Main
Year: 2013
Date: 23 April
Mode: Online
Subject: Chemistry
Chapter: Some Basic Concepts of Chemistry

JEE Main 2013 · 23 April · Online · Chemistry · Some Basic Concepts of Chemistry

Number of atoms in the following samples of substances is largest...

Number of atoms in the following samples of substances is largest in:

Options

A $4.0 \mathrm{~g}$ of hydrogen
B $71.0 \mathrm{~g}$ of chlorine
C $127.0 \mathrm{~g}$ of iodine
D $48.0 \mathrm{~g}$ of magnesium

Correct answer

A. $4.0 \mathrm{~g}$ of hydrogen

Step-by-step solution

4 \mathrm{ g}

of hydrogen=4

mole of hydrogen

=4 \times 6.023 \times 10^{23}

atoms

\begin{aligned} & 71.0 \mathrm{gm} \text{ of chlorine }=\frac{71.0}{71.0}=1 \text{ moles of } \\ & \text{ chlorine } \\ & 127 \mathrm{gm} \text{ of iodine }=\frac{1}{2} \text{ mole of }_2 \\ & =\frac{127}{254}=6.023 \times 10^{23} \text{ atoms } \\ & 48.0 \mathrm{gm} \text{ of magnesium } \\ & =\frac{48.0}{24.0}=2 \times 6.023 \times 10^{23} \times \frac{1}{2} \text{ atoms } \\ & \therefore 4.0 \mathrm{gm} \mathrm{H}_2 \text{ has largest number of atoms. } \end{aligned}

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