Electrochemistry

Cell with Salt Bridge Cell with Salt Bridge A Daniel Cell can be substitute by a design as showing in diagram above. The chemical reaction remains the same as the Daniel cell. Using salt bridge can reduce the internal resistance of the cell. The function of the salt bridge is to allow ions follow from … Read more

Daniel Cell The Daniell cell was invented in 1836 by a British chemist name John Frederic Daniell. It was invented to eliminate the hydrogen bubble problem found in the simple voltaic cell. The Daniell cell consist of a zinc electrode and a copper electrode. The zinc electrode is immersed in zinc sulphate solution (or sulphuric acid) … Read more

Simple Voltaic Cell A simple voltaic cell consists of two metal plates of different metals immerse in an electrolyte. The metal which is higher in electrochemical series will become the negative terminal. The atom of the metal which is higher in electrochemical series will release electron to form negative ions. The electrons are then move … Read more

Industrial Applications of Electrolysis – Purifying of Copper Copper is a good electrical conductor and is used extensively to make electrical wiring and components. However, the presence of impurity in copper can reduce its electrical conductivity. In industry, electrolysis processed is used to purify copper, and the process is called electrolytic refining. Electrolytic Refining of … Read more

Industrial Applications of Electrolysis – Electroplating Electroplating is a process to coat an object with a thin protective layer of metal Electroplating is used to prevent corrosion improve the appearance of the objects In electroplating, the anode is the electroplating metal the cathode is the object to be electroplated the electrolyte must contain the ions … Read more

Extraction of Metals Diagram below shows the methods of extraction for different metals. Metals which are less reactive than carbon in reactivity series are extracted from their ore by displacement reaction using carbon. Copper and mercury can be extracted from their ore by burning directly in air. Silver (Ag) and gold (Au) need no extraction … Read more

Factors Affecting the Selective Discharge – Types of Electrode Type of Electrode There are 2 types of electrode: Inert electrodeInert electrodes do not react with electrolyte and do not take part in the chemical reaction. (Example: Carbon, platinum) Active electrodeThe active electrode will react with the electrolyte and take part in the reaction. (Example: Copper, Silver, … Read more

Factors Affecting the Selective Discharge – Concentration If the concentration of a particular ion is high, it may be selected to be discharged even though it is higher in the electrochemical series compares with another ion present in the solution. Example Electrolysis of Diluted Hydrochloric Acid Electrolysis of Concentrated Hydrochloric Acid Ions presence atAnode:Cl–, OH– … Read more

Factors Affecting the Selective Discharge – Electrochemical series The tendency of ions to be selected to be discharged at an electrode depends on their position in a series called the electrochemical series. The ions at the top of the list is more difficult to be discharged, but as we go down the table, they become … Read more

Electrolysis of Aqueous Solution An aqueous solution is solution of water of a substance. For example, if you heat sodium chloride until it melts, it is called molten sodium chloride, but if you dissolve sodium chloride in water, it is called aqueous sodium chloride. Electrolysis of aqueous solution is different from electrolysis of molten electrolyte … Read more