Question

Which ion can be most easily reduced cu2+ Zn2+ Ni2+ ca2+

Answer 1

The answer is A. Cu ^2+

Answer 2

Answer : Cu²⁺ ion can be most easily reduced.

Explanation :

Let us write the reduction reactions and the associated standard reduction potentials for the given ions.

1)
`Cu^(2+) + 2e^(-)\rightarrow Cu`
`E^(0)_(red)= 0.34 V`

2)
`Zn^(2+) + 2e^(-)\rightarrow Zn`
`E^(0)_(red)= -0.76 V`

3)
`Ni^(2+) + 2e^(-)\rightarrow Ni`
`E^(0)_(red)= -0.26 V`

4)
`Ca^(2+) + 2e^(-)\rightarrow Ca`
`E^(0)_(red)= -2.87 V`

If we look at the above standard reduction potential values, we see that standard reduction potential is highest for Cu²⁺ ion.

Higher the standard reduction potential, greater is the ability to undergo reduction.

Since Cu²⁺ ion has the highest standard reduction potential, it can be most easily reduced.