Acids are substances that can donate protons or hydrogen ions (H⁺) in a solution. They often have a sour taste and can be found in many everyday items, such as lemons and vinegar. When acids dissolve in water, they release these hydrogen ions, which can make the solution more acidic. In chemistry, acids are classified based on their strength. Strong acids, like hydrochloric acid, completely dissociate in water, while weak acids, like acetic acid, only partially dissociate. Acids play a crucial role in various chemical reactions and are essential in many industries, including food production and pharmaceuticals.