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What Is the Electrolysis of Sulfuric Acid?

Lee Johnson
Lee Johnson

The electrolysis of sulfuric acid is the process which causes different components of a sulfuric acid mixture to be collected at two electrodes. This occurs because the sulfuric acid solution contains charged particles called ions. These particles collect at the electrode with the opposite charge in electrolysis. Hydrogen gas collects at the cathode, or the negatively charged electrode. Oxygen gas collects at the anode, or the positively charged electrode.

Understanding the electrolysis of sulfuric acid requires knowledge of ions. Ions are particles which have either a positive or negative electromagnetic charge. This occurs because the original element has lost or gained an electron, resulting in an imbalance between the number of electrons and protons. Electrons are negatively charged particles and protons are positively charged particles. Normal atoms have an equal number of electrons and protons and therefore do not have a charge. Ions are formed so that the element can bond with other elements in ionic bonding.

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Woman holding a book

Electrolysis is the process of splitting up compounds by splitting the positive ions from the negative ones. This occurs as a result of electromagnetism, which is the force which causes negative charges to be attracted to positive ones, and vice versa. The electrolysis of sulfuric acid uses this law of physics to break up ionic compounds. Scientists insert two electrodes into a chemical solution and send an electric current through them. This causes the positive ions to move to the cathode and gain electrons and the negative ions to move to the anode and lose electrons.

During the electrolysis of sulfuric acid, the negatively charged hydroxide (OH-) ions are drawn to the anode. Hydroxide ions have more electrons than protons, and are therefore negatively charged. They then lose electrons and are converted into oxygen gas and water. The lost electrons cause the ionic bond between hydrogen and oxygen to break down, meaning that the remaining hydrogen and oxygen can form water. In an electrolysis reaction of four hydroxide ions, the four hydrogen atoms bond with two oxygen ones to form water and leave two molecules of oxygen (O2) free to escape as gas.

Hydrogen gas (H2) is created at the cathode in the electrolysis of sulfuric acid. This occurs because the positively charged hydrogen ions (H+) are drawn to the negatively charged cathode. The electrons flowing through the electrode are added to the hydrogen to convert it back into hydrogen gas. The negative charges from the electrons balance out the hydrogen ions and convert them back into their gaseous form.

Discussion Comments


What is the actual direction of current or electron flow? How does it take place and how does it potentially play a role in electric current? On what basis should we differentiate between a cathode and and an anode?

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