june 2018- paper 1

Question 1

stages of heterogeneous catalyst activity (3)

Answer 1

• reactants adsorbed onto the active site
• reaction happens on the surface
• desorbtion of the product

Question 2

oxide that could react with water to form a solution with pH 2

Answer 2

SO2

Question 3

anhydrous AlCl3 reaction with water

Answer 3

AlCl3 + 6H2O > [Al(H2O)6]3+ + 3Cl–

Question 4

how [Al(H2O)6]3+ can react with an acid

Answer 4

[Al(H2O)6]3+ + H2O > [Al(H2O)5(OH)]2+ + H3O+

Question 5

[Al(H2O)6]3+ + Na2CO3

Answer 5

2[Al(H2O)6]3+ + 3CO32– > 2[Al(H2O)3(OH)3] + 3CO2 + 3H2O

white ppt and bubbles

Question 6

[Al(H2O)6]3+ + KOH

Answer 6

[Al(H2O)6]3+ +3OH– > [Al(H2O)3(OH)3] + 3H2O (white ppt)

then [Al(H2O)3(OH)3] + OH- > [Al(OH)4]– + 3H2O (ppt dissolves)