Account for the following:
1)Halo alkanes have higher boiling point than the corresponding parent alkane.
2)Boiling point of halo alkanes RIRBrRCl RF
3)Boiling point of 1-Bromo butane 2-Bromo butane 1-Bromo- 2-methylpropane 2-Bromo- 2-methyl propane.
4)Melting point of p-Dichlo benzene is higher than its ortho and meta isomer.
5)Halo alkanes are polar in nature but sparingly soluble in water.
6)Iodo alkane can not be prepared by the reaction of alcohol with KI and sulphuric acid. Phosphoric acid is used in place of sulphuric acid.
7)Order of reactivity of alcohol with HX is tert alcohol sec alcohol primary alcohol..
8)Halo arenes can not be prepared by treating phenol with HX or NaX in the presence of sulphuric acid.
9)Iodination of benzene is carried out in the presence of HIO3or HNO3.
10)Propane on chlorination gives 2-chloro propane as a major product and not 1-chloro propane.
11)Kharasch effect is possible only with HBr and not with HCl and HI.
12)Alcohol reacts with thionyl chloride to give pure halo alkane.
13)Finkelstein reaction of halo alkane is carried out in the presence of dry acetone.
14)Order of reactivity of halo alkanes as per substitution bimolecular nucleophilic is primary halide secondary halidetertiary halide.
15)Order of reaction as per substitution unimolecular is tertiary halidesecondary halide primary halide.
16) Benzylic halides and allylic halides are more reactive towards nucleophile than halo alkanes.
17)Chloro ethene is less reactive towards nucleophile than chloro ethane.
18)Halo arenes are less reactive towards nucleophile than halo alkanes.
19)SN1 mechanism is ruled out in the reaction of halo arenes with nucleophile.
20)Electron with drawing groups like NO2at ortho and para position with respect to halogen facilitates nucleophillic substitution reaction.
21)Electron with drawing groups like NO2at meta position with respect tohalogen has no effect on nucleophillic substitution reaction.
22)Halo arenes are less reactive towards electrophile than benzene.
23)Although chlorine atom has electron with drawing effect electrophillic substitution occur at ortho and para position.
24)Order of reactivity of alkyl halide RIRBrRClRF
25)Halo alkanes react with KCN to give alkyl cyanide as a major product while it gives alkyl isocyanide as a major product with AgCN.
26)Halo alkanes give nitrito alkane with KNO2while nitro alkane with AgNO2.
27) CH3I undergoes SN2reaction faster than CH3Cl.
1. Boiling point of haloalkanes is higher as compared to their parent alkane due to the increased molecular weight of the large halogen atoms, the increased intermolecular forces due to the polar bonds and the increasing polarizabilty of the halogen atom.
5. Haloalkanes are sparingly soluble and they do not dissolve in water due to their inability to form hydrogen bonds with water molecules.