The standard reduction potential for Cu2+/Cu  is +0.34 V. The reduction potential at pH = 14 for the above couple is [Ksp[Cu(OH)2]=1.0×10−19]

pH=14∴pOH=0, (or) [OH−]=10−0=1Therefore [Cu2+]=Ksp[OH−]2=1×10−19(1)2=1×10−19ECu2+/Cu=ECu2+/Cuo−0.0592×19                   = 0.34-0.03×19                   =-0.22V