Question

A battery charger used to recharge NiMH batteries can deliver as much as 0.800 A of current to each battery. If it takes 100. min to recharge one battery, how much Ni(OH)2 (in grams) is oxidized to NiO(OH)?

Answer 1

Answer: 4.6 grams

Step-by-step explanation:

1 electron carry charge=
`1.6* 10^(-19)C`

1 mole of electrons contain=
`6.023* 10^(23)` electrons

Thus 1 mole of electrons carry charge=
`(1.6* 10^(-19))/(1)* 6.023* 10^(23)=96500C`

`A^(n+)\rightarrow A+ne^-`

`Q=I* t`

where Q= quantity of electricity in coloumbs

I = current in amperes = 0.800A

t= time in seconds = 100 min= 6000 sec (1min=60sec)

`Q=0.800A* 6000s=4800C`

96500C charge is carried by = 1 mole of electrons

4800C charge is carried by=
`(1)/(96500)* 4800=0.05moles`

`Mass={\text {no of moles}}* {\text {Molar mass}}=0.05moles* 92.708g/mol=4.6g`

Thus 4.6g of
`Ni(OH)_2` is oxidized to
`NiO(OH)`.