How do oxides of phosphorus react with water? Why aluminum oxide is amphoteric? How does it react with acids and bases? Present examples. Would a free transition metal ion (for example Fe3+ dissolved in a solvent with no ligands surrounding the metal ion) generate any color? Explain why or why not. Solution Phosphorus forms two common oxides, phosphorus(III)oxide (P 4 O 6 ) and phosphorus(V)oxide (P 4 O 10 ). P 4 O 10 is the acid anhydride of phosphorous acid, H 3 PO 3 that is produced whenP4O6 dissolves slowly in cold water. The balanced equation is below P4O6 + 6H2O = 4H3PO3 P4O10 molecule is the acid anhydride of orthophosphoric acid, H3PO4. When P4O10 is reacted with water, it makes a hissing sound, heat is liberated, and the acid is formed. As it has affinity for water, P4O10 is used extensively as a drying agent for gases and for removing water from many compounds.The balanced equation is below P4O10 + 6H2O = 4H3PO4 Aluminium oxide is amphoteric i.e it can react with both acid and base. As you move from left to right across the periodic Table from Na to Cl, electropositivity decreases from left to right. Aluminum has an electronegativity of about 1.6, exactly at the boundary where oxides of elements start becoming acidic. Al being on the boundary  is equally likely to give off or attract oxygens. In acidic conditions, protons in the solution will protonate the oxygen forming water and Aluminium\'s corresponding salt. For example Al 2 O 3 + 6 HF ? 2 AlF 3 + 3 H 2 O In basic coditions however, hydroxide ions promote the formation of more hydroxide ions from Al’s oxygens forming a hydrated aluminate complex and water. The reaction here is little bit complicated than a regular acid-base reaction. For example Al2 O 3 + Na OH ? NaAlO2 + H2O Electrons are arranged around the nucleus of the metal atom in orbitals. Transition metals, unlike other metals, have partially filled ‘d’ orbitals, which can hold up to 10 electrons. In presence of ligands some d orbitals become higher in energy than before and some become lower. Electrons can then move between these higher and lower d orbitals by absorbing a photon of light. The perceived colour of the compound or complex depends on the wavelength of the light absorbed. A free transition metal ion when present in aqueous solution, the water molecules will directly attached to the metal and act as a ligand. For example color of Fe3+, when dissolved in water generate very pale violet/brown color. So, a free transition metal ion can generate color depending on in which solvent it is dissolved. .

1. How do oxides of phosphorus react with water?
Why aluminum oxide is amphoteric? How does it react with acids and bases? Present examples.
Would a free transition metal ion (for example Fe3+ dissolved in a solvent with no ligands
surrounding the metal ion) generate any color? Explain why or why not.
Solution
Phosphorus forms two common oxides, phosphorus(III)oxide (P 4 O 6 ) and phosphorus(V)oxide
(P 4 O 10 ). P 4 O 10 is the acid anhydride of phosphorous acid, H 3 PO 3 that is produced
whenP4O6 dissolves slowly in cold water. The balanced equation is below
P4O6 + 6H2O = 4H3PO3
P4O10 molecule is the acid anhydride of orthophosphoric acid, H3PO4. When P4O10 is reacted
with water, it makes a hissing sound, heat is liberated, and the acid is formed. As it has affinity
for water, P4O10 is used extensively as a drying agent for gases and for removing water from
many compounds.The balanced equation is below
P4O10 + 6H2O = 4H3PO4
Aluminium oxide is amphoteric i.e it can react with both acid and base. As you move from left to
right across the periodic Table from Na to Cl, electropositivity decreases from left to right.
Aluminum has an electronegativity of about 1.6, exactly at the boundary where oxides of
elements start becoming acidic. Al being on the boundary  is equally likely to give off or
attract oxygens. In acidic conditions, protons in the solution will protonate the oxygen forming
water and Aluminium's corresponding salt. For example
Al 2 O 3 + 6 HF ? 2 AlF 3 + 3 H 2 O
In basic coditions however, hydroxide ions promote the formation of more hydroxide ions from
Al’s oxygens forming a hydrated aluminate complex and water. The reaction here is little bit
complicated than a regular acid-base reaction. For example
Al2 O 3 + Na OH ? NaAlO2 + H2O

2. Electrons are arranged around the nucleus of the metal atom in orbitals. Transition metals, unlike
other metals, have partially filled ‘d’ orbitals, which can hold up to 10 electrons. In
presence of ligands some d orbitals become higher in energy than before and some become
lower. Electrons can then move between these higher and lower d orbitals by absorbing a photon
of light. The perceived colour of the compound or complex depends on the wavelength of the
light absorbed. A free transition metal ion when present in aqueous solution, the water molecules
will directly attached to the metal and act as a ligand. For example color of Fe3+, when dissolved
in water generate very pale violet/brown color. So, a free transition metal ion can generate color
depending on in which solvent it is dissolved.