Electrolysis of Water & Hydrochloric Acid | Reactions | Chemistry | FuseSchool
TLDRThis script explores the fundamentals of electrolysis, a process named by Michael Faraday, who also coined terms like 'anode' and 'cathode.' It explains how adding sulfuric acid to water enhances electrolysis without changing the products, which are hydrogen and oxygen gases, collected in a 2:1 ratio. The script delves into the redox reactions occurring at the electrodes, with oxygen forming at the anode through oxidation and hydrogen at the cathode through reduction. It also notes that acidifying water with hydrochloric acid alters the reaction, producing chlorine gas at the anode. Safety precautions with chlorine's toxicity are highlighted.
Takeaways
- 🔋 The discovery of splitting water using electric current happened soon after the discovery of current electricity.
- 🧪 Michael Faraday introduced most of the terms used in electrolysis today.
- 🔍 Electrolysis means using electricity to split something apart, a term coined by Faraday.
- ⚡ The electrolysis cell consists of a positive anode and a negative cathode.
- 💧 Pure water is a poor conductor of electricity because it barely ionizes at room temperature.
- 🧴 Adding sulfuric acid to water improves its ability to undergo electrolysis without changing the products.
- 🌊 Electrolysis produces gas bubbles at both electrodes, more at the cathode.
- ⚙️ Using a Hofmann voltammeter, gases from electrolysis can be collected in a 2:1 ratio.
- 🔄 The balanced equation of electrolysis gives gases in a two-to-one ratio, hydrogen to oxygen.
- 🔋 In redox reactions during electrolysis, oxygen forms at the anode and hydrogen forms at the cathode.
Q & A
Who discovered that passing an electric current through water would split it apart?
-The discovery was made quite soon after the discovery of current electricity itself, predating Michael Faraday's work in this area.
Who introduced most of the terms used in electrolysis today?
-Michael Faraday introduced most of the terms used in electrolysis.
What does the term 'electrolysis' mean, and who named it?
-Electrolysis means using electricity to split something apart, and it was named by Michael Faraday.
What equipment is used in electrolysis and who named most of it?
-The equipment includes a cell with a positive anode and a negative cathode, electrodes connected to the cell, and the liquid being electrolyzed, called the electrolyte. Most of this equipment was named by Faraday.
Why is pure water a poor conductor of electricity?
-Pure water is a poor conductor of electricity because it is a covalent molecule that hardly ionizes at room temperature, resulting in a very small concentration of free ions needed to carry current.
How can the ability of water to undergo electrolysis be increased without altering the products obtained?
-By adding a little sulfuric acid to water, the ability of water to undergo electrolysis is greatly increased without altering the products obtained.
What gases are produced during the electrolysis of water, and in what ratio?
-During the electrolysis of water, bubbles form around both electrodes, with more around the cathode. The gases produced are in a ratio of two to one.
What are the ions present in water and what do they do during electrolysis?
-The ions present in water are the hydrogen ion and the hydroxide ion. These ions are attracted to the electrode with the opposite charge during electrolysis.
What reactions occur at the anode and cathode during the electrolysis of water?
-At the anode, oxygen is made through a loss of electrons, which is an oxidation reaction. At the cathode, hydrogen is made by gaining electrons, which is a reduction reaction.
How does acidifying water with hydrochloric acid alter the electrolysis reaction?
-When water is acidified with hydrochloric acid, the presence of chloride ions alters the reaction, resulting in the oxidation of chloride anions and the production of chlorine gas at the anode instead of oxygen.
Why must precautions be taken when working with chlorine in the lab during electrolysis?
-Precautions must be taken because chlorine is toxic and very soluble in water, requiring care to avoid exposure.
Outlines
🔬 The Discovery and Terminology of Electrolysis
This paragraph delves into the early discovery of passing an electric current through water to split it apart, predating Michael Faraday's work. Faraday, however, introduced most of the terminology we use today, including the term 'electrolysis,' which means using electricity to split something apart. The paragraph explains the basic equipment used in electrolysis, named by Faraday: a cell with a positive anode and a negative cathode, electrodes, and the electrolyte. Pure water, being a poor conductor due to its covalent nature, requires sulfuric acid to enhance its electrolyzing ability. The paragraph concludes by describing the formation of bubbles around both electrodes and the collection of gases in a two-to-one ratio using a Hofmann voltammeter.
💧 Ion Behavior and Redox Reactions in Electrolysis
This paragraph provides a detailed look at the ions present in water—hydrogen ions and hydroxide ions—and their attraction to electrodes with opposite charges. It explains Faraday's terminology of 'anions' (ions that go to the anode) and 'cations' (ions that go to the cathode). At the anode, oxygen is produced through an oxidation reaction, while at the cathode, hydrogen is produced via a reduction reaction, leading to an overall redox reaction. The paragraph highlights the two-to-one ratio of gases formed and introduces the mnemonic 'oil-rig' (Oxidation Is Loss, Reduction Is Gain) to track electrons in redox reactions.
⚗️ Effects of Hydrochloric Acid on Electrolysis
This paragraph discusses how acidifying water with hydrochloric acid alters the electrolysis reaction due to the presence of chloride ions (Cl-). Instead of hydroxide ions, chloride anions are oxidized, producing chlorine gas at the anode instead of oxygen. The reaction remains a redox reaction, but the gases are produced in equal amounts. The paragraph notes that chlorine's higher solubility in water compared to hydrogen means it takes longer to observe appreciable amounts of chlorine gas. It ends with a safety reminder about chlorine's toxicity and the importance of taking precautions when working with it in a lab setting.
Mindmap
Keywords
💡Electrolysis
💡Michael Faraday
💡Anode
💡Cathode
💡Electrolyte
💡Ion
💡Covalent Molecule
💡Oxidation
💡Reduction
💡Redox Reaction
💡Hofmann Voltammeter
💡Acidification
Highlights
The discovery that passing an electric current through water would split apart was made soon after the discovery of current electricity.
Michael Faraday introduced most of the terms used in electrolysis today.
Faraday named electrolysis, which means to use electricity to split something apart.
Electrolysis equipment includes a cell with a positive anode and a negative cathode.
Pure water is a poor conductor of electricity due to its low ionization at room temperature.
Adding sulfuric acid to water increases its ability to undergo electrolysis without changing the products.
Bubbles form around both electrodes during electrolysis, with more around the cathode.
Using a Hofmann voltammeter, gases produced can be collected and are made in a ratio of two to one.
The initial solubility of oxygen in water sometimes masks the two to one gas ratio.
Hydrogen ions and hydroxide ions in water are attracted to electrodes with opposite charges.
Faraday called the ions moving to the anode anions and those to the cathode cations.
Oxygen is produced at the anode, which is an oxidation reaction, while hydrogen is produced at the cathode, a reduction reaction.
The overall reaction is a redox reaction, producing gases in a two to one ratio.
If water is acidified with hydrochloric acid, chloride ions are oxidized, producing chlorine instead of oxygen at the anode.
Chlorine gas is more soluble in water than hydrogen, delaying its visibility in the experiment.
Chlorine is toxic, requiring precautions when working with it in the lab.
Transcripts
Browse More Related Video
5.0 / 5 (0 votes)
Thanks for rating: