Physics, asked by akanksha135, 1 year ago

Hey please help me with this question!

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Answered by MyselfAbhi
1
Here's the answer correctly:
The reaction taking place in the question:

At anode: Mn2+(aq) + 2H2O(L) --> MnO2(s) + 4H(aq) 2e-
At cathode: 2H+(aq) + 2e --> H2(g)
Overall reaction: Mn2(aq) + 2H2O(l) --> MnO2(s) + 2H+(aq) + H2(g)

Amount of current is given by -
I = m . FxZ/txM

Where m is the weight of MnO2 = 1kg = 1000g[given]
F= Faraday's constant 
t= time required 
Z= no. of electrons transferred 
M= mass of Mn02 = (55+32)= 87 g/mol 
Substituting these values, we get: 
I = 1000 g [ 95600C/mol x 2/24x60x60x87] 
= 25.67 A 
Now current efficiency = 25.67/27 x 100% = 95.07% = 95%

Hence the answer is option B
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