5.5 periodic table 🪑

Question 1

reaction of sodium oxide with water

Answer 1

reacts vigorously to form a strongly basic solution
Na2O + H2O -> 2NaOH

Question 2

reaction of magnesium oxide with water

Answer 2

reacts less vigorously to form a weakly alkaline solution; sparingly soluble due to more exothermic lattice energy
MgO +H2O -> Mg(OH)2

Question 3

reaction of aluminium oxide with water (ionic with covalent character)

Answer 3

does not react due to very exothermic lattice energy

Question 4

reaction of silicon oxide with water

Answer 4

does not react due to strong and extensive covalent bonds between atoms

Question 5

reaction of phosphorus oxide with water

Answer 5

react readily to form acidic solution
P4O6 + 6H2O -> 4H3PO4

Question 6

reaction of sulfur oxide with water

Answer 6

react readily to form acidic solution
SO3 + H2O -> H2SO4

Question 7

reaction with aluminium oxide with acids and bases

Answer 7

Al2O3 + 6HCl -> Al2Cl3 + 3H2O
Al2O3 + 2NaOH + 3H2O -> 2NaAl(OH)4

Question 8

reaction of sodium chloride with water

Answer 8

dissolves in water with complete hydrolysis to form hydrated ions in a pH 7 solution
NaCl -> Na+ + Cl-

Question 9

reaction of magnesium chloride with water

Answer 9

dissolves in water with partial hydrolysis to give a slightly acidic solution (pH6)
MgCl2 + 6H2O -> [Mg(H2O)6]2+ + 2Cl-
[Mg(H2O)6]2+ + H2O <=> [Mg(H2O)5(OH)]+ H3O+

Question 10

reaction of aluminium chloride with water

Answer 10

dissolves in water with partial hydrolysis to give an acidic solution (pH 3)
AlCl3 + 6H2O -> [Al(H2O)6]3+ + 3Cl-
[Al(H2O)6]3+ + H2O <=> [Al(H2O)5(OH)]3+ + H3O+

Question 11

reaction of silicon chloride with water

Answer 11

dissolves in water with complete hydrolysis to form strongly acidic solution (pH2)
SiCl4 + 2H2O -> SiO2 + 4HCl

Question 12

reaction of phosphorus chloride with water

Answer 12

dissolves in water with complete hydrolysis to form strongly acidic solution (pH2)
PCl5 + 4H2O -> H3PO4 + 5HCl

Question 13

reaction of phosphorus chloride with limited cold water

Answer 13

white fumes of HCl are observed
PCl5 + H2O -> POCl3 + 2HCl