Hydrocarbons
What two elements make up all hydrocarbons?
Carbon and hydrogen
What is a functional group?
A group of atoms responsible for characteristic reactions of a compound.
What are the conditions needed for the substitution of methane with bromine?
UV light (photochemical reaction)
What type of mechanism occurs when methane reacts with bromine under UV light?
Free radical substitution
What does CFC stand for?
Chlorofluorocarbon
What type of bonds are found between carbon atoms in alkanes?
Single covalent bonds (C–C)
What functional group is found in alcohols?
Hydroxyl (–OH)
What reagent and conditions are required for the hydrogenation of ethene to ethane?
Hydrogen gas, nickel catalyst, 150 °C
What initiates this substitution reaction?
Ultraviolet light (causes homolytic fission of Br–Br bond)
Why were CFCs banned or restricted?
They deplete the ozone layer, producing toxic breakdown products.
Which hydrocarbon has the formula C₂H₄ and contains a double bond?
Ethene
What is the suffix used for carboxylic acids?
–oic acid
Under what conditions does dehydration of ethanol to ethene occur?
Concentrated sulfuric acid, heat (170 °C)
What type of mechanism occurs when ethene reacts with bromine?
Electrophilic addition
What is a modern replacement for CFCs used in refrigerants?
Hydrofluorocarbons (HFCs)
How does the reactivity of alkenes differ from that of alkanes?
Alkenes are more reactive due to the presence of a π bond (double bond).
What is the IUPAC name of CH₃CH₂COOH?
Propanoic acid
What reagent and conditions are needed to convert a halogenoalkane into an alcohol?
Aqueous NaOH, heat under reflux
In electrophilic addition, what bond breaks — homolytically or heterolytically?
Heterolytically
What property makes halogenoalkanes useful as solvents but environmentally risky?
They are volatile and stable in the atmosphere.
Explain why alkanes are described as “saturated.”
All carbon atoms have single bonds; no more hydrogen can be added without breaking bonds.
Identify the functional groups present in CH₃COOCH₂CH₃.
Ester group (–COO–)
Compare the conditions for substitution vs elimination of halogenoalkanes.
Substitution: aqueous conditions, lower temp; Elimination: ethanolic NaOH, higher temp
Explain why iodoalkanes react faster in nucleophilic substitution than bromoalkanes.
The C–I bond is weaker (lower bond enthalpy), so it breaks more easily.
Explain one industrial or environmental importance of organic reaction mechanisms.
Used in drug synthesis, polymer production, and understanding pollutant degradation.