Question

An alloy of lead (valency = 2) and thallium (valency = 1) containing 65% $Pb$ and 35% $Tl$, by weight, can be electroplated onto a cathode from a solution. How many gram of this alloy will deposit in 9.65 hours using a constant current of 0.5 amp?

[Given that only these two elements deposit simultaneously in given mass ratio at cathode]

[Atomic weight $Pb=208,Tl=200$]

• A. 3.7 gm
• B. 22.5 gm
• C. 37 gm
• D. 24.9 gm

Answer 1

The correct option is C 37 gm

$w=\frac{E}{F}\times$ It ($E-$ equivalent weight)

for $Pb=\frac{208\times .5\times 9.65\times 3600}{2\times 96500}=37.44$

$65\%$ od $37.44=24.336$

for $TI=\frac{200\times .5\times 9.65\times 3600}{1\times 96500}\times \frac{35}{100}=12.6$

$12.6+29.336\approx 37gm$

COMMENT = correct ans is $C$