Medium MCQ +4 / -1 PYQ · JEE Mains 2023

When $\mathrm{Cu}^{2+}$ ion is treated with $\mathrm{KI}$, a white precipitate, $\mathrm{X}$ appears in solution. The solution is titrated with sodium thiosulphate, the compound $\mathrm{Y}$ is formed. $\mathrm{X}$ and $\mathrm{Y}$ respectively are :

  1. A <style type="text/css"> .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-0lax{text-align:left;vertical-align:top} </style> <table class="tg" style="undefined;table-layout: fixed; width: 362px"> <colgroup> <col style="width: 148px"> <col style="width: 214px"> </colgroup> <thead> <tr> <td class="tg-0lax">$\mathrm{X=CuI_2}$</td> <td class="tg-0lax">$\mathrm{Y=Na_2S_4O_6}$</td> </tr> </thead> </table>
  2. B <style type="text/css"> .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-0lax{text-align:left;vertical-align:top} </style> <table class="tg" style="undefined;table-layout: fixed; width: 362px"> <colgroup> <col style="width: 148px"> <col style="width: 214px"> </colgroup> <thead> <tr> <td class="tg-0lax">$\mathrm{X=Cu_2I_2}$</td> <td class="tg-0lax">$\mathrm{Y=Na_2S_4O_6}$</td> </tr> </thead> </table> Correct answer
  3. C <style type="text/css"> .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-0lax{text-align:left;vertical-align:top} </style> <table class="tg" style="undefined;table-layout: fixed; width: 362px"> <colgroup> <col style="width: 148px"> <col style="width: 214px"> </colgroup> <thead> <tr> <td class="tg-0lax">$\mathrm{X=CuI_2}$</td> <td class="tg-0lax">$\mathrm{Y=Na_2S_2O_3}$</td> </tr> </thead> </table>
  4. D <style type="text/css"> .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-0lax{text-align:left;vertical-align:top} </style> <table class="tg" style="undefined;table-layout: fixed; width: 362px"> <colgroup> <col style="width: 148px"> <col style="width: 214px"> </colgroup> <thead> <tr> <td class="tg-0lax">$\mathrm{X=Cu_2I_2}$</td> <td class="tg-0lax">$\mathrm{Y=Na_2S_4O_5}$</td> </tr> </thead> </table>

Solution

$2 \mathrm{Cu}^{2+}+4 \mathrm{KI} \longrightarrow \underset{\text { White ppt. }}{\mathrm{Cu}_{2} \mathrm{I}_{2}}+\mathrm{I}_{2}$ <br/><br/>$\mathrm{I}_{2}+\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3} \longrightarrow 2 \mathrm{Nal}+\mathrm{Na}_{2} \mathrm{~S}_{4} \mathrm{O}_{6}$ <br/><br/>$\mathrm{X}=\mathrm{Cu}_{2} \mathrm{I}_{2}$ <br/><br/>$\mathrm{Y}=\mathrm{Na}_{2} \mathrm{~S}_{4} \mathrm{O}_{6}$

About this question

Subject: Chemistry · Chapter: d and f Block Elements · Topic: Properties of Transition Metals

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