halogenoalkanes Flashcards
What is the general formula for halogenoalkanes?
What type of atoms replace hydrogen in halogenoalkanes?
Halogen atoms
Why is the C-X bond in halogenoalkanes polar?
Halogens are more electronegative than carbon
How does electronegativity change down group 7?
Electronegativity decreases
What physical property of halogenoalkanes is affected by chain length?
Boiling point increases with chain length
What happens to boiling point as you move down the halogen group?
Boiling point increases
What effect does increased branching have on melting point?
Increased branching lowers the melting point
Why do halogenoalkanes have higher boiling points than alkanes?
Due to higher masses and polar bonds
How does reactivity of the C-X bond change down the group?
Reactivity increases down the group
Why do fluoroalkanes have low reactivity?
Due to the strong C-F bond
What is a nucleophile?
A negatively charged ion with a lone pair of electrons
What does a nucleophile do in nucleophilic substitution?
Donates its electrons to an electron deficient carbon atom
What are the products of nucleophilic substitution with primary halogenoalkanes?
Alcohol, nitrile, or amine
What type of halogenoalkane undergoes elimination reactions?
Tertiary halogenoalkanes
What is formed in an elimination reaction?
Alkene and water
What conditions favor nucleophilic substitution with hydroxide ions?
Aqueous and warm
What conditions favor elimination with hydroxide ions?
Ethanolic and hot
What is the overall equation for nucleophilic substitution with NaOH?
R-X + NaOH → R-OH + NaX
What is ozone’s chemical formula?
O_3
Where is ozone formed naturally?
In the stratosphere, about 20-40 km above the surface
What is the role of ozone in the atmosphere?
Absorbs ultraviolet radiation
What happens to oxygen molecules under UV radiation?
They break down into oxygen radicals
What is the effect of CFCs on the ozone layer?
They contribute to ozone depletion
How do chlorine atoms affect ozone?
They catalyse the decomposition of ozone
What is the overall reaction for ozone decomposition in the presence of chlorine?
2O_3 → 3O_2 with Cl• as the catalyst
What type of reactions do halogens undergo?
Reactions of halogenoalkanes
