Name: ________________________
Bonding 3
Class: ________________________
Date: ________________________
Time: 38 minutes
Marks: 33 marks
Comments:
Page 1 of 11
, Q1.
Halogenoalkanes such as 1,1,2-trichloro-1,2,2-trifluoroethane were used as coolants in
refrigerators until the late 1980s. Their use was then banned and alternative coolants
were used instead.
(a) Draw the displayed formula of 1,1,2-trichloro-1,2,2-trifluoroethane.
(1)
(b) 1,1,2-Trichloro-1,2,2-trifluoroethane was banned for use as a refrigerant because it
damaged the ozone layer.
Write three equations to show how this compound is involved in damaging the
ozone layer.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(3)
(c) State the role of chlorine atoms in the reactions in part (b).
___________________________________________________________________
(1)
(d) Inevitably, some coolant escapes from refrigerators.
Deduce which of the following coolants, A, B or C, would cause least environmental
damage to the atmosphere.
CHCl2CHClF CF3CH2F CF3CCl2F
A B C
Coolant ________
(1)
(e) Give the IUPAC name of compound B in part (d).
___________________________________________________________________
(1)
(f) The boiling point of iodomethane (CH 3I) is higher than that of fluoromethane (CH 3F)
even though the electronegativity of iodine is less than that of fluorine.
Page 2 of 11
Bonding 3
Class: ________________________
Date: ________________________
Time: 38 minutes
Marks: 33 marks
Comments:
Page 1 of 11
, Q1.
Halogenoalkanes such as 1,1,2-trichloro-1,2,2-trifluoroethane were used as coolants in
refrigerators until the late 1980s. Their use was then banned and alternative coolants
were used instead.
(a) Draw the displayed formula of 1,1,2-trichloro-1,2,2-trifluoroethane.
(1)
(b) 1,1,2-Trichloro-1,2,2-trifluoroethane was banned for use as a refrigerant because it
damaged the ozone layer.
Write three equations to show how this compound is involved in damaging the
ozone layer.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(3)
(c) State the role of chlorine atoms in the reactions in part (b).
___________________________________________________________________
(1)
(d) Inevitably, some coolant escapes from refrigerators.
Deduce which of the following coolants, A, B or C, would cause least environmental
damage to the atmosphere.
CHCl2CHClF CF3CH2F CF3CCl2F
A B C
Coolant ________
(1)
(e) Give the IUPAC name of compound B in part (d).
___________________________________________________________________
(1)
(f) The boiling point of iodomethane (CH 3I) is higher than that of fluoromethane (CH 3F)
even though the electronegativity of iodine is less than that of fluorine.
Page 2 of 11
