Haloalkane

• What are haloalkanes?

  Alkanes with at least one hydrogen replaced by a halogen
• How are haloalkanes with two different halogen atoms named?

  In alphabetical order
• Why can haloalkanes be attacked by nucleophiles?

  Due to the slightly positive carbon atom
• What type of bond is created by an electronegative halogen atom in a haloalkane?

  A polar C—X bond
• Why does water react more slowly as a nucleophile compared to other nucleophiles?

  It reacts more slowly than other nucleophiles
• What are haloalkanes hydrolysed into in nucleophilic substitution reactions?

  Alcohols
• What conditions are required for the hydrolysis of haloalkanes?

  Warm aqueous alkali
• During heterolytic bond breaking, which atom takes both bonding electrons?

  The halogen
• In the reaction mechanism for nucleophilic substitution, what does the hydroxide ion do?

  Attacks the slightly positive carbon
• What products are formed in the nucleophilic substitution reaction of haloalkanes with hydroxide ions?

  An alcohol and a halide ion
• Besides an alcohol and halide ion, what other product is formed when water is the nucleophile?

  A hydrogen ion
• What is the main reason for different rates of hydrolysis among different haloalkanes?

  Differences in carbon-halogen bond enthalpy
• Which carbon-halogen bond has the highest bond enthalpy?

  C—F
• Which haloalkane reacts the slowest?

  Fluoroalkanes
• Which haloalkane reacts the fastest?

  Iodoalkanes
• What is dissolved in ethanol in the experimental method for testing hydrolysis rates?

  A different haloalkane
• What reagent is added to react with halide ions formed in the substitution reaction?

  Silver nitrate
• What type of product is formed when silver nitrate reacts with halide ions?

  Silver halide precipitates
• What color is silver chloride precipitate?

  White
• In what solution is silver chloride precipitate soluble?

  Dilute ammonia solution
• What color is silver bromide precipitate?

  Cream
• In what solution is silver bromide precipitate soluble?

  Concentrated ammonia solution
• What color is silver iodide precipitate?

  Yellow
• In what solution is silver iodide precipitate soluble?

  Insoluble in aqueous ammonia
• Which precipitate is expected to appear first in the hydrolysis experiment?

  Pale yellow solid (AgI)
• Why were CFCs used in aerosols and fridges?

  Because they are very stable
• What elements do chlorofluorocarbons contain?

  Chlorine and fluorine
• Why were CFCs banned?

  They produce holes in the ozone layer
• What does the ozone layer protect us from?

  UV radiation
• What is the chemical formula for ozone?

  O3
• What are free radicals?

  Species with unpaired electrons
• How is ozone formed in the upper atmosphere?

  UV radiation breaks oxygen molecules
• What type of fission produces oxygen free radicals from oxygen molecules?

  Homolytic fission
• How are chlorine radicals formed from CFCs?

  By UV radiation breaking C—Cl bonds
• What role do chlorine radicals play in ozone depletion?

  Catalyzing its breakdown into oxygen
• Besides chlorine radicals, what other radicals contribute to ozone layer depletion?

  Nitrogen oxide radicals
• How are nitrogen oxides produced?

  Vehicle engines and thunderstorms
• How are nitrogen oxide radicals formed?

  UV light breaks N—O bonds
• What role do Cl and NO free radicals play in the ozone layer depletion reaction?

  They act as catalysts
• When were CFCs banned?

  1970s