Corrosion Chemistry and Electrochemical Series

The galvanic series is a list of metals and alloys arranged in order of their corrosion tendencies, with more anodic materials placed higher in the series.

Unlike the electrochemical series, which primarily focuses on the reactivity of metals, the galvanic series specifically indicates the corrosion behavior of metals and alloys.

The calomel electrode is used as a reference electrode in the galvanic series.

<p>A higher position in the galvanic series indicates that the metal is more anodic and will undergo corrosion faster.</p> Signup and view all the answers

<p>The electrochemical series provides a measure of the reactivity of metals, indicating that those with a lower reduction potential are more anodic and more prone to corrosion.</p> Signup and view all the answers

<p>The electrochemical series is measured by dipping pure metals in their 1M salt solution.</p> Signup and view all the answers

<p>The galvanic series is advantageous because it provides specific predictions about the behavior of metals and alloys in a corrosive environment, unlike the broader electrochemical series.</p> Signup and view all the answers

<p>If a metal is anodic in the galvanic series, it means that it will corrode preferentially when in contact with a less anodic metal.</p> Signup and view all the answers

<p>Hydrogen is oxidized to H+ ions at the anode, generating electrons that flow to the cathode.</p> Signup and view all the answers

<p>The positive electrode is made of LiCoO2 or Li2O.Co2O3, and the negative electrode is made of graphite.</p> Signup and view all the answers

<p>The temperature is maintained at about 200°C to enhance the ionic conductivity of phosphoric acid, which is low at lower temperatures.</p> Signup and view all the answers

<p>The SEI acts as a separator between the anode and cathode, allowing ion transport while preventing electronic conduction.</p> Signup and view all the answers

<p>Full charging can lead to excessive lithium ion extraction, which may destabilize the crystal structure and affect the battery's performance.</p> Signup and view all the answers

<p>Cooling plates are used to manage the heat generated during the reaction to maintain the desired operating temperature.</p> Signup and view all the answers

<p>H+ ions are transported to the cathode where they combine with oxygen and electrons to form water.</p> Signup and view all the answers

<p>At the anode, LiCoO2 is oxidized, releasing Li+ ions and electrons.</p> Signup and view all the answers

<p>Cobalt ions are reduced from Co4+ to Co3+ as lithium ions migrate back to the cathode.</p> Signup and view all the answers

<p>H+ ions produced at the anode replenish the H+ ion deficiency at the electrolyte side.</p> Signup and view all the answers

<p>Lithium ions migrate through the electrolyte and are reduced to lithium atoms, which then insert themselves between the carbon layers in graphite.</p> Signup and view all the answers

<p>Hydrogen gas is passed through the anodic chamber, while oxygen gas is passed through the cathodic chamber.</p> Signup and view all the answers

<p>The overall reaction involves the oxidation of hydrogen to H+ ions and electrons at the anode, and the reduction of oxygen with H+ ions and electrons to form water at the cathode.</p> Signup and view all the answers

<p>They are called lithium-ion batteries because they operate through the movement of lithium ions rather than lithium metal.</p> Signup and view all the answers

<p>The pressure in the cell is maintained at 50 atm to facilitate the effective reaction between hydrogen and oxygen gases.</p> Signup and view all the answers

<p>Maintaining electrical neutrality ensures stability within the lattice and prevents structural degradation.</p> Signup and view all the answers

<p>Hydrogen-oxygen fuel cells can convert about 80% of available chemical energy to electrical energy.</p> Signup and view all the answers

<p>The primary byproduct is water, which is beneficial as it causes no pollution and can be used for drinking in space stations.</p> Signup and view all the answers

<p>A key challenge is that gaseous fuels are difficult to store and handle.</p> Signup and view all the answers

<p>The main component is the solid mercurous chloride (Hg2Cl2 or calomel) in contact with a potassium chloride solution.</p> Signup and view all the answers

<p>Hydrogen-oxygen fuel cell technology is considered expensive due to the high costs of obtaining pure fuels and suitable catalysts.</p> Signup and view all the answers

<p>One operational benefit is that they can supply energy continuously as long as the reactants are fed.</p> Signup and view all the answers

<p>The Nernst equation is given as E = E° - (RT/nF) ln(Q), or in simplified form E = E° - 59/n log(Q) at 25°C.</p> Signup and view all the answers

<p>The calomel electrode's construction involves a glass tube with mercury and solid mercurous chloride, ensuring a stable electrochemical environment.</p> Signup and view all the answers

<p>The Pt wire serves to make electrical contact with the mercury layer, facilitating the electrode's function.</p> Signup and view all the answers

<p>The potential of the calomel electrode varies directly with the concentration of KCl solution; higher concentrations yield different potentials.</p> Signup and view all the answers

<p>The calomel electrode acts as a cathode when its electrode potential is higher than that of the coupled electrode.</p> Signup and view all the answers

<p>The saturated calomel electrode is preferred because its emf remains consistent and does not change with chemical reactions.</p> Signup and view all the answers

<p>The side tube is used to make electrical contact with a salt bridge, linking the calomel electrode to the electrochemical cell.</p> Signup and view all the answers

<p>The calomel electrode will undergo oxidation.</p> Signup and view all the answers

<p>The electrolyte used is highly corrosive, which poses handling and maintenance challenges.</p> Signup and view all the answers

<p>The term 'E°' represents the standard electrode potential.</p> Signup and view all the answers

<p>The calomel electrode can act as either anode or cathode, depending on its potential relative to the coupled electrode.</p> Signup and view all the answers

<p>The oxidation reaction at the calomel electrode decreases the overall cell potential.</p> Signup and view all the answers