Halogenoalkanes and Hydrolysis Reactions Flashcards
what are halogenoalkanes simply
a homologous series of compounds
what is the general formula of a halogenoalkane
CnH(2n+1)X
what are halogenaalkanes the result of
replacing a hydrogen atom in a hydrocarbon with a halogen atom
what does the X in the general formula for a halogenoalkane represent
a halogen
what does the symbol R represent in organic chemistry
an alkyl group
what could the formula of a halogenoalkane therefore be shortened to with that symbol
RX
what would the general formula of a hydrocarbon with two or three halogen atoms bonded to it be
- CnH2nX2 for two
- CnH(2n-1)X3 for three
what is the name of CH2Cl-CHCl-CH3
1,2-dichloropropane
what is the name of CH2Br-CH2(CH3)-CH2Cl
1-bromo-3-chloro-2-methylpropane
for 1-bromo-3-chloro-2-methylpropane, why is the bromine atom named first rather than the chlorine atom
because you name them in alphabetical order
what is CH3-CH2-CH2F classified to be and why
- a primary halogenoalkane
- because the carbon atom the halogen atom is bonded to is only bonded to one other carbon atom itself
- meaning it is only bonded to one alkyl group
what is CH3-CHBr-CH3 classified to be and why
- a secondary halogenoalkane
- because the carbon atom that the halogen atom is bonded to is bonded to two other carbon atoms itself
- meaning it is bonded to two alkyl groups
what is (CH3)2CCl-CH2-CH3 classified to be and why
- a tertiary halogenoalkane
- because the carbon atom the halogen atom is bonded to is bonded to three carbon atoms itself
- meaning it is bonded to three alkyl groups
why are most bonds in hydrocarbons non-polar
- because they only contain carbon and hydrogen atoms
- which have similar electronegativities
why is the C-X bond in halogenoalkanes polar
because the halogen atom has a higher electronegativity than that of carbon
what does it mean if an atom is electronegative
they attract electrons
how does the electronegativity of the group 7 elements change as you go down the group
the electronegativity decreases
what would the partial charges between a carbon and halogen atom be if halogen atoms are more electronegative
- C(sigma +)-X(sigma -)
- the carbon atom would be partially positively charged while the halogen atom would be partially negatively charged
what would you call the carbon atom in this case
electron deficient
what does the difference in the electronegativities of hydrocarbons and halogenoalkanes mean about how their level of reactivity compares
- halogenoalkanes are more reactive than hydrocarbons
- this is because the halogen atoms are more electronegative than them
- meaning the halogen is partially negatively charged while the carbon is more partially positively charged than it would be with a hydrogen atom
- meaning halogenoalkanes are more unstable and therefore are more reactive
what do these carbon atoms with partially positive charges attract
nucleophiles
what are nucleophiles
- species that are attracted to slightly positive or electron deficient parts of a molecule
- they are either negative ions or molecules with a slightly negative atom
- but always use a lone pair of electrons when attacking other species
when a halogenoalkane is mixed with water, why does a reaction occur between the two
- the water molecule contains polar bonds like the halogenoalkane
- the o- oxygen atom is attracted to the o+ carbon atom of the halogenoalkane
what is the general formula for the reaction between a halogenoalkane and water
- RX + H2O = ROH + HX
- or RX + H2O = ROH + H+ + X-
what is therefore the product of the reaction between halogenoalkanes and water
an alcohol
what type of reaction is this and why
- hydrolysis
- hydro = water and lysis = splitting
- so it is simply splitting with water
