Chemistry

There are two types of electrochemical Corrosion: Galvanic corrosion Differential aeration or Concentration cell corrosion Galvanic corrosion When two dissimilar metals are in contact with each other on the presence of aqueous solution or moisture, galvanic corrosion occurs. The more active metal (with high negative electrode potential and higher in the electrode potential and higher

Based on the corrosion of metals in the nature of the environment it is classified into two types: Dry or chemical corrosion. Wet or electrochemical corrosion. S.No Dry or chemical corrosion Wet or electrochemical corrosion 1 Occurs in a dry state. Occurs in the presence of moisture of electrolyte. 2 Involves direct chemical attack on

Chemistry of Corrosion Most of the metals (except noble metals like gold, platinum etc.) exist in nature as ores (metallic oxide, sulphide, carbonate, silicate etc.). By metallurgical operations, these ores are converted into pure metals. The pure metal will always have higher energy than its ore or metallic compound. The pure metal at higher energy

The following are some examples for corrosion that we experience in our day to day life. (i) Rusting of iron : Iron exposed to the environment forms a brown rust film on its surface. (ii) Water stored in aluminium vessel : If water is stored for a long time in an aluminium vessel, white spots

Here are a few simple electrochemistry solved problems along with their solutions: 1. Calculate the single electrode potential of copper metal immersed in 0.15°MCu2+ solution. E° for copper is +0.34 V at 25°C. Solution: By Nernst equation [latex] \mathrm{E}=\mathrm{E}^{\circ}+\frac{0.0592}{\mathrm{n}}\left[\log \mathrm{M}^{\mathrm{n}+}\right] at 25^{\circ} \mathrm{C} [/latex] [latex] \begin{aligned} & =0.34+\frac{0.0592}{2} \log [0.15] \\ & =0.34+\frac{0.0592}{2}(-0.8239)=0.3156 \mathrm{~V} \end{aligned} [/latex] 2. Calculate the electrode potential of

Definition : When elements are arranged in increasing order of their standard reduction electrode potentials, the series so obtained is known as electrochemical (or) electromotive series. or A series in which standard reduction potentials of various electrodes are arranged in the order of increasing reduction potentials (largest reduction potential at the top) or decreasing oxidation

Nernst equation can be used to calculate the emf of the cells when the concentration of reactants and products are known. Let us consider a general redox reaction Mn+ + ne– [latex] \rightleftharpoons [/latex] M. For any reversible reaction, the change in free energy ΔG and equilibrium constant K can be related using van’t Hoff’s isotherm as

It is impossible to know the absolute values of the single electrode potential. It is because a single electrode constitutes only a half- cell. A half-cell would not lose or gain electrons by itself. The loss or gain of electrons can take place only in a complete circuit containing two half- cells connected to each

Definition : Measure of tendency of a metallic electrode to lose or gain electrons when it is in contact with its own ions in solution is called electrode potential. When an electrode, say a metal, is immersed in a solution of its ions, then there can be two possibilities: (i) Mn+ ions may collide with

The cells used for electrolysis are called electrolytic cells while those used for generation of electrical energy from chemical reactions are called galvanic or voltaic cells. The practical application of a galvanic cell is Daniel cell. The electrode where oxidation occurs is called anode and the electrode where reduction occurs is called cathode. John Daniell