transition metals

• In aqueous solution (Fe(H2O)6)2+ is a green solution
• In aqueous solution (Cu(H2O)6)2+ is a blue solution
• In aqueous solution (Fe(H2O)6)3+ is a pale violet (appears orange due to hydrolysis to some (Fe(H2O)5(OH))2+
• In aqueous solution (Al(H2O)6)3+ is a colourless solution
• When NaOH is added dropwise, (Fe(H2O)4(OH)2) is a green precipitate (darkens due to oxidation when standing), no further reaction when NaOH added excess
• When NaOH is added dropwise, (Cu(H2O)4(OH)2) is a blue precipitate, no further reaction when NaOH added excess
• When NaOH is added dropwise, (Fe(H2O)3(OH)3) is a brown precipitate, no further reaction when NaOH added excess
• When NaOH is added dropwise, (Al(H2O)3(OH)3) is a white precipitate, when excess NaOH is added, it re-dissolves to give a colourless solution (Al(H2O)2(OH)4)-
• When NH3 is added dropwise, (Fe(H2O)4(OH)2) is a green precipitate, (darkens on standing due to oxidation), no further reaction when NH3 added excess
• When NH3 is added dropwise, (Cu(H2O)4(OH)2) is a blue precipitate, when NH3 added in excess, (Cu(H2O)2(NH3)4)2+ is a deep blue solution
• When NH3 added dropwise, (Fe(H2O)3(OH)3) is a brown precipitate, no further reaction when NH3 added excess
• When NH3 added dropwise, (Al(H2O)3(OH)3) is a white precipitate, no further reaction when NH3 added excess
• When Na2CO3 is added, FeCO3 is a green precipitate
• When Na2CO3 is added, CuCO3 is a blue-green precipitate
• When N2CO3 is added, (Fe(H2O)3(OH)3) is a brown precipitate and effervesces (CO2)
• When Na2CO3 is added, (Al(H2O)3(OH)3 is a white precipitate and effervesces (CO2)
• When conc. HCl is added, (FeCl4)2- is a yellow solution
• When conc. HCl is added, (CuCl4)2- is a green solution
• When conc. HCl is added, (FeCl4)- is a yellow solution
• When conc. HCl is added, (AlCl4)- is a colourless solution
• The acidity of M3+ ions is greater than M2+ ions due to their higher charge density and smaller size. This higher charge density leads to a stronger attraction between the M3+ ion and the water ligands, weakening the O-H bonds and facilitating the release of hydrogen ions, thus increasing acidity
• variable oxidation states are crucial for transition metals in catalysis because they allow these metals to readily accept or donate electrons, facilitating the formation of temporary bonds with reactants and lowering the activation energy of reactions, thus speeding up the process