The standard hydrogen electrode is A. used to calibrate voltmeters. B. used to produce a set of standard reduction potentials. C. needed to activate electrochemical cells. D. often overlooked in measuring standard reduction potentials. E. used to produce a standard cell potential of exactly 1 V.

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.