3.3.3 Halogen Alkanes

Question 1

Would a chloro, bromo or iodo alkane react the fastest and why

Answer 1

Iodo, the C-I bond has the lowest bond enthapy so is the easiest to break

Question 2

Describe how chlorine atoms are formed in the upper atmosphere

Answer 2

When ultraviolet radiation causes C–Cl bonds in chlorofluorocarbons (CFCs) to break

Question 3

Equations when chlorine atoms catalyse the decomposition of ozone and contribute to the hole in the ozone layer

Answer 3

Cl• + O3 —> ClO• + O2
ClO• + O3 —> 2O2 + Cl•

Question 4

CFC advantages

Answer 4

Unreactive
Non-flammable
Non-toxic

Question 5

CFCs are

Answer 5

Banned as solvents and refrigerants