Acids, Bases and Salts - Properties of acids and bases

Acids are defined as proton donors ($H^+$ ions) according to the Brønsted-Lowry theory. When dissolved in water, they produce hydrogen ions, $H^+(aq)$.

Bases are defined as proton acceptors. Soluble bases are called alkalis and produce hydroxide ions, $OH^-(aq)$, in aqueous solutions.

The $pH$ scale ranges from $0$ to $14$. $pH < 7$ indicates an acidic solution, $pH = 7$ is neutral (e.g., pure water), and $pH > 7$ indicates an alkaline solution.

Strong acids, such as $HCl$, $H_2SO_4$, and $HNO_3$, dissociate completely in water. Weak acids, such as $CH_3COOH$ (ethanoic acid), dissociate only partially.

Common indicators: Litmus (red in acid, blue in base), Phenolphthalein (colorless in acid, pink in base), and Methyl orange (red in acid, yellow in base).

Acids react with reactive metals to produce a salt and hydrogen gas: $Acid + Metal \rightarrow Salt + H_2(g)$.

Acids react with carbonates to produce a salt, water, and carbon dioxide: $Acid + Carbonate \rightarrow Salt + H_2O(l) + CO_2(g)$.

Neutralization occurs when an acid reacts with a base (or alkali) to form a salt and water: $H^+(aq) + OH^-(aq) \rightarrow H_2O(l)$.

Amphoteric oxides, such as $Al_2O_3$ and $ZnO$, are oxides that can react with both acids and bases to form salts and water.