JEE PYQ: Electrochemistry Question 16
Question 16 - 2020 (04 Sep Shift 2)
250 mL of a waste solution obtained from the workshop of a goldsmith contains 0.1 M AgNO$_3$ and 0.1 M AuCl. The solution was electrolyzed at 2 V by passing a current of 1 A for 15 minutes. The metal/metals electrodeposited will be:
$(E^0_{\text{Ag}^+/\text{Ag}} = 0.80$ V, $E^0_{\text{Au}^+/\text{Au}} = 1.69$ V$)$
(1) only gold
(2) silver and gold in proportion to their atomic weights
(3) only silver
(4) silver and gold in equal mass proportion
Show Answer
Answer: (1) only gold
Solution
Moles of $e^-$ passed = 0.0093 mol. Species with higher SRP deposits first. Au$^+$ needs 0.025 mol $e^-$ but only 0.0093 available. So only Au deposits.
BETA
