How long (approximate) should water be electrolysed by passing through 100   amperes   current so…

How long (approximate) should water be electrolysed by passing through 100 amperes current so that the oxygen released can completely burn 27.66 g of diborane? (Atomic weight of B=10.8 u)
  1. 1.6 hours
  2. 6.4 hours
  3. 0.8 hours
  4. 3.2 hours

Solution

B2H6+3O2→B2O3+3H2O
According to balanced equation
27.66 g B2H6 i.e. 1 mole B2H6 requires 3 mole of O2 . Now this oxygen is produced by electrolysis of water as follows
2H2O→4F2H2+O2
As 1 mole O2 is produced by 4 F charge
So 3 mole O2 will be produced by 12 F charge
So now on applying
Q = It
12×96500C=100×t(s)
t=12×96500100×3600 hours
t=3.2 hours

Asked in: JEE Main 2018 (08 Apr)

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