It"s a humale tendency to compare ourselves to someone else. Can I run quicker than you? Am I taller than my dad?—these are loved one comparisons that do not providemuch advantageous data. When we use a standard for our comparisons, one point is much more comparable to an additional. One meter is the exact same distance all over in the human being, so a 100 meter track in one country is exactly the very same distance as a 100 meter track in another country—this isa global basis for the comparikid of a running time, for instance.

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Standard Hydrogen Electrode

The activity series enables us to predict the loved one reactivityof various products as soon as provided in oxidation-reduction procedures. We additionally know we can develop electric current by a combination of jiyuushikan.orgical procedures. But exactly how execute we predict the meant amount of current that will certainly flow via the system? We meacertain this flow as voltage (an electromotive pressure or potential difference).

In order to execute this, we need some method of comparing the level of electron flow in various jiyuushikan.orgical units. The ideal method to execute this is to have actually a baseline that we use—a conventional that everything deserve to be measured versus. For determicountry of half-reaction current flows and also voltperiods, we usage the conventional hydrogen electrode. The figure below illustprices this electrode. A platinum wire conducts the electricity via the circuit. The wire is immersed in a (1.0 : extM) strong acid solution and (ceH_2) gas is bubbled in at a press of one environment and a temperature of (25^ exto extC). The half-reactivity at this electrode is (ceH_2 ightarrowhead 2 ceH^+ + 2 cee^-).

Figure (PageIndex1): The traditional hydrogen electrode.

Under these problems, the potential for the hydrogen reduction is defined as precisely zero. We call this (E^0), the typical reduction potential.

We can then usage this mechanism to measure the potentials of various other electrodes in the half-cell. A metal and among its salts (sulfate is often used) is in the second half-cell. We will certainly usage zinc as our example (see figure below).

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Figure (PageIndex2): The traditional hydrogen half-cell paired with a zinc half-cell.

As we observe the reactivity, we alert that the mass of solid zinc decreases during the course of the reactivity. This suggests that the reaction occurring in that half-cell is: