250   mL of a waste solution obtained from the workshop of a goldsmith contains 0 . 1   M  …

250 mL of a waste solution obtained from the workshop of a goldsmith contains 0.1 M AgNO3 and 0.1M AuCl. The solution was electrolyzed at 2 V by passing a current of 1 A for 15 minutes. The metal/metals electrodeposited will be : EAg+/Ag0=0.80V,EAu+/Au0=1.69V
  1. only gold
  2. silver and gold in proportion to their atomic weights
  3. only silver
  4. silver and gold in equal mass proportion

Solution

 Charge (q)= it 96500F=1×15×6096500=90096500=9965F=0.0093 F

No. of moles of Au+=0.025 & No. of moles of Ag+=0.025

Species with higher value of SRP will get deposited first at cathode.

(i) Au+(aqs) + e-⟶ Au(s)

0.025          0.0093 mole 

so only Au will get deposited.

Asked in: JEE Main 2020 (04 Sep Shift 2)

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