Match List - I with List - II.
| List I (Salt) | List II (Flame colour wavelength) | ||
|---|---|---|---|
| (a) | LiCl | (i) | 455.5 nm |
| (b) | NaCl | (ii) | 670.8 nm |
| (c) | RbCl | (iii) | 780.0 nm |
| (d) | CsCl | (iv) | 589.2 nm |
Choose the correct answer from the options given below :
Solution
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<tr>
<th class="tg-amwm">Alkali metal</th>
<th class="tg-amwm">Colour (Flame)</th>
<th class="tg-amwm">$\lambda$ (nm)</th>
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</thead>
<tbody>
<tr>
<td class="tg-baqh">Li</td>
<td class="tg-baqh">Crimson red</td>
<td class="tg-baqh">670.8</td>
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<td class="tg-baqh">Na</td>
<td class="tg-baqh">Yellow</td>
<td class="tg-baqh">589.2</td>
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<td class="tg-baqh">Rb</td>
<td class="tg-baqh">Red, violet</td>
<td class="tg-baqh">780.0</td>
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<td class="tg-baqh">Cs</td>
<td class="tg-baqh">Blue</td>
<td class="tg-baqh">455.5</td>
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<p>Alkali metals have very low value of ionisation energy as compared to other metals. So, alkali metals easily get excited and impart colour to flame.</p>
<p>Hence, Rb is most excited and having high value of wavelength in all alkali metals.</p>
About this question
Subject: Chemistry · Chapter: s-Block Elements · Topic: Alkali Metals
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