hi everyone welcome to igcc study Budd where you can revise chemistry topics from the Cambridge igcc syllabus if you are enjoying our videos so far please don't forget to hit the like button and subscribe to our channel in this video you are going to learn part one of topic four electrochemistry electrolysis is the decomposition of an ionic compound when molten or in Aqua Solution by the passage of an electric current so basically electrolysis involves breaking apart ionic compounds using electricity remember that the ionic compound should be either melted or in water so that they have free ions in order to allow electricity to pass through let's look at a simple electrolytic cell this is an electrode an electrode is a conductor often a metal or graphite Rod that allows electric current to go in or out of an electrolyte the electrolyte is the molten or aquous substance that undergoes electrolysis molten means heated until it becomes a liquid and aquous means dissolved in water now just a quick reminder if an atom loses electrons it becomes a positively charged ion known as a cation if it gains or takes in electrons it becomes a negatively charged ion called an anion if you watched our video part three of chapter 2 atoms elements and compounds you might remember this visual representation to remember that cations are positively charged and annion are negatively charged the cathode is the negative electrode opposite charges attract so the negative charge on the cathode pulls the positive charg cat I towards it so cathodes attract positively charged cat the anode is the positive electrode it attracts the negatively charged annion towards it here's a tip to remember which electrode is positive and which is negative a cathode attracts cat that's easy to remember since both start with cat we already learned that a cat is a positively charged ion remember this picture where I put the positive sign instead of the T in cation remember opposite charges attract each other so if a cathode attracts positive ions then it must be negative likewise an anode attracts anion this is also easy to remember since both start with n annion are negatively charged ions remember the word negative when you look at the letter N in an ion opposite charges attract so if an anode attracts negative ions then it must be the opposite which is positive during electrolysis an electric current is required to flow through the circuit at the power supply it is the electrons that carry this electric charge through the external circuit the electrons move from the power supply to the cathode making it negatively charged the anode becomes positively charged as it loses electrons the positive cations in the electrolyte move towards the cathode where they gain electrons the negative annion in the electrolyte move towards the anode where they lose electrons the electrons from the anode move back towards the power supply when the current flows in the electrodes and wires it is the electrons that carry the electrical charge when the current flows in an electrolyte it is the ions that move and carry the electrical charge we should be able to predict the identity of the products at each electrode during electrolysis as we just learned please remember that the positive ion or cation will always move towards the cathode and the negative ions or an I will always move to the anode the electrolyte can be either a molten compound or an aquous solution a binary compound is a chemical compound composed of two different elements molten compounds are in a liquid state due to being being heated to a high temperature typically above their melting points so if the electrolyte is a binary molten ionic compound we know that once it under goes electrolysis the ions in the electrolyte will be just the two elements that make up the compound example in N the ions present will be na+ and cl minus during electrolysis we mainly look at how electrons move when ions touch the electrode electrons are either lost or gained creating neutral substances these neutral substances are then released as products at the electrodes at the anode negative ions lose electrons this is oxidation so oxidation is when something loses electrons and at the cathode positive ions gain electrons this is reduction so reduction is when something gains electrons an easy way to remember this is the pneumonic oil rig oxidation is loss of electrons and reduction is gain of electrons we use ionic half equations to show these processors making sure the charges are balanced for example for the electrolysis of molten sodium chloride these will be the ionic half equations at the anode two chloride ions lose use two electrons to form cl2 gas so it's rearranged to be written like this at the cathode sodium ions gain an electron to form sodium that concludes part one of topic four electrochemistry are you enjoying our videos are they helping you here's a way you you can show your appreciation and support our continued efforts you may use YouTube super thanks to send us thanks hope this video helped you please share your thoughts and suggestions in the comment section thank you for watching and please don't forget to subscribe to igcc study bu for more revision videos bye-bye