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.