Strong & Weak Acids

• Strong acids ionise completely, which means all the acid particles will dissociate (reactants turn completely into products). Hydrochloric acid and nitric acid are stong acids.
• Weak acids do not fully ionise, because their ionisation is reversible. So this means the reactants can form the products and the products can react to form reactants. We say the equilibrium lies to the left.
• Being strong or weak is all about what proportion of the acid particles ionise in water.
• Concentration is a measure of how much acid there is in a certain volume.
• pH is a measure of the concentration of H+ ions in a solution. As the concentration of H+ ions increases, pH gets lower. A decrease of 1 on the pH scale represents the concentration of H+ increasing by 10x.
• At any given concentration a strong acid will always have a lower pH than a weak acid.