A solution containing a mixture of metal cations was treated with dilute HClHCl and no precipitate formed. Next, H2SH2S was bubbled through the acidic solution. A precipitate formed and was filtered off. Then, the pH was raised to about 88 and H2SH2S was again bubbled through the solution. A precipitate again formed and was filtered off. Finally, the solution was treated with a sodium carbonate solution, which resulted in no precipitation. Classify the metal ions based on whether they were definitely present, definitely absent, or whether it is possible they were present in the original mixture.

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.