Question

The number of Faradays of electricity required,
to decompose 100 ml water, (density = 0.99
gm/ml) is
1) 2 2) 11 3) 100 4) 5.5
​

Answer 1

Answer:

option 2 ) 11 is correct.

The number of Faradays of electricity required,

to decompose 100 ml water = 11

Explanation:

given :

density = 0.99gm/ml

it means that 100ml water weighs 99 gm

moles= given wt / molecular wt

         = 99/18                            molecular wt of $H_{2}$O = 18 gm$mol^{-1}$

         = 5.5 moles

decomposition of water:

2$H_{2}$O -----> 4$H^{+}$ + 2$O^{2-}$

2$O^{2-}$ -------> $O_{2}$ + 4$e^{-}$

4$H^{+}$ +   4$e^{-}$ -------> 2$H_{2}$

The number of Faradays of electricity required,

to decompose 100 ml water   =  Number of moles of electron required to decompose 100 ml water

Number of moles of electron required to decompose 2 moles of water = 4

Number of moles of electron required to decompose 5.5 moles of water = 11 moles.

Hope it helps !