1.

A solution of Ni(NO_(3))_(2) is electrolysed between platinum electrodes using a current of 5 amperes for 20 minutes. What mass of Ni is deposited at the cathode ?

Answer»

Solution :* Mass of electricity `Q=5Axx20xx60s`
=6000C
* By the following reaction NI is formed.
Ionization : `Ni(NO_(3))_(2(aq)) to Ni_((aq))^(2+)+2NO_(3(aq))^(-)`
REDUCTION on cathode:
`Ni_((aq))^(2+) + underset("2 mol "e^(-))(2e^(-)) to underset("1 mol Ni")(Ni_((l)))`
* According to this reaction, 2 mol `e^(-)`, 2F electricity 1 mol `Ni=58.7` g Ni
So, `2xx96500` COULOMB electricity produce 58.79 gm Ni and so mass of Ni obtained by using 6000 coulomb electricity
`=(6000xx58.79)/(2xx96500)`
`=1.8277g` Ni


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