EΘ values of some redox couples are given below. On the basis of these values choose the correct option.

EΘvalues:Br2/Br-=+1.90
Ag+/Ag(s)=+0.80
Cu2+/Cu(s)=+0.34;
I2(s)/I-=+0.54

1. Cu will reduce Br 2. Cu will reduce Ag
3. Cu will reduce I 4. Cu will reduce Br2
Hint: High reduction potential substance is a good oxidising agent
The given values of E° are as follows:
Br2/Br-=+1.90V
Ag/Ag+=-0.80V
Cu2+/Cu(s)=+0.34V
I-/I2(s)=-0.54V
Br-/Br2=-1.90V
The E° values show that copper will reduce Br2, if the E° of the following redox reaction is positive.
2Cu+Br2CuBr2
CuCu2++2e-;E°=-0.34V
Br2+2e-2Br-;E=+1.09VCu+Br2CuBr2;E°=+0.75V
Since, E° of this reaction is positive, therefore, Cu can reduce Br2.
While other reaction will give negative value.