ALKENES

In polar solvent H2O, e- cloud of Br2 is polarised by polar H2O molecules, causes Br2 to have partial charge separation, causes Br atom to be more e- def and have a larger partial positive charge Br molecule in H2O is more susceptible to Nu attack by alkane molecules

____ is the major pdt as the tertiary C+ int formed during E-add is more stable than the secondary C+ int that leads to the minor pdt ___ The tertiary C+ has more e- donating alkyl groups attached to the positively charged C+ thus the +ve charge is dispersed to a larger extent, ist is more stable and thus__ is formed faster and becomes the major pdt

-HI > HBr > HCl, HI is the most reactive -From Cl to I, atomic radius ↑ -effectiveness of orbital overlap ↓ - bond strength ↓, ↓amt of energy req to break H-X bonds

• C+ int is trigonal planar, - the Cl/Br- Nu can attack the positively charged Carbon from either sides of the plane w/ equal probability -equal proportions of 2 enantiomers are formed, resulting in racemic mixt -the 2 enantiomers rotate PPL in opposite directions by the same extent -thus optically inactive

1) Br2 in CCl OR Br2(aq) to each sample @rtp -> alkene undergoes E-Add and decolourises orange-red Br2 -> remains orange red for alkane 2)Cold dilute KMnO, dilute KOH -> alkene undegoes [O], decolourises purple KMnO4, brown ppt MnO2 is formed -> purple colour remains for alkane and no ppt is formed 3)KMnO4, dilute H2SO4, heat using water bath -> alkene undergoes strong [O] and decolourises purple KMnO, effervescence of CO2 gas which forms white ppt in limewater ->purple colour remains for alkane and no effervescence formed

[Li+Al H4]- forms H- hydride ion which repels from the e- rich C=Chi

its e-rich π-bond tends to repel nucleophiles OR since C-H and C=C bonds are non polar, there are no e-def sites for Nu attack