[sta6a2411]

Any metal lower than hydrogen in the electrochemical series, i.e. with a positive electrode potential, can be deposited at the cathode during electrolysis.
But electrode potential of Chromium and Nickel is negative.
H+ ion should be reduce to give hydrogen gas before Chromium ions and Nickel ions. Am I wrong??
If so, how does nickel and chromium electroplating work exactly??

[chenbeier]

They using additives to change the potential.

[Borek]

Hydrogen evolves at 0.0V only when the activity of H⁺ equals 1 - that means pH 0. Change the pH and the potential changes as well, as given by the Nernst equation.