JEE Main On 08 April 2018 Question 10
Question: 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) [JEE Main Online 08-04-2018]
Options:
A) $ 3\text{.2 hours} $
B) $ 1\text{.6 hours} $
C) $ 6\text{.4 hours} $
D) $ 0\text{.8 hours} $
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Answer:
Correct Answer: A
Solution:
$ B _2H _6+3O _2(g)\xrightarrow{{}}B _2O _3+3H _2O(\ell ) $
moles $ =\frac{27.66}{27.6}=1 $ 1mole of $ {B_2}{H_6} $
required 3 moles of $ {O_2} $ $ 2H _2O(\ell )\xrightarrow{{}}O _2(g)+4{H^{+}}(aq)+4{e^{-}} $
$ \frac{It}{96500}= $ mole of $ O _2\times n _{f} $
$ \frac{100\times t\times 3600}{96500}=3\times 4\Rightarrow t=3.2hrs $
