What is the principal difference between a strong acid and a weak acid? Strong acids have high concentrations of the hydroxide ion while in solution. When neutralized, strong acids form salt and water while weak acids only form water. Strong acids completely ionize while weak acids only partially ionize. Strong acids are polyprotic while weak acids are monoprotic.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.