Acids produce H+ ions in solution. Bases/alkalis produce OH− ions. pH scale: 0-6 acidic, 7 neutral, 8-14 alkaline.
Neutralisation: H+ + OH− → H2O
Acid reactions:
Acid + Metal → Salt + Hydrogen
Acid + Metal oxide → Salt + Water
Acid + Metal hydroxide → Salt + Water
Acid + Metal carbonate → Salt + Water + CO2
Salt names: HCl → chloride, H2SO4 → sulfate, HNO3 → nitrate.
Strong acids (HCl, H2SO4) fully ionise in water. Weak acids (ethanoic acid, citric acid) partially ionise — same concentration but higher pH.