Give the decreasing order of net dipole moments of the following:
Text Solution
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a. `I gt II gt III` (I). , (I) has a smaller angle of separation between two `Br` atoms than in (II) and (III) resulting in more net dipole moment `(mu)`. (II). , (II) has a large angle of separation between two `Br`. atoms therefore, net `(mu)` is less than (I). (III) , In (III), two `Br` atoms and two `H` atoms have equal and opposite bond moments, therefore, net `mu` is zero. b.`I gt II`. (I). , Due to `vec(e )`- withdrawing `(-I)` effect of two `Br` atoms and `vec(e )`- donating `(+I)` effect of two `Me` atoms in the same direction, net resultant dipole moment is more. (II). , Due to `vec(e )`-withdrawing `(-I)` effect of two `Br` atoms and `vec(e )` donating `(+I)` effect of two `Me` atoms, there is equal and opposite bond moment. Hence net resultant is zero.
, (I) has a smaller angle of separation between two `Br` atoms than in (II) and (III) resulting in more net dipole moment `(mu)`. 
, (II) has a large angle of separation between two `Br`. atoms therefore, net `(mu)` is less than (I). 
, In (III), two `Br` atoms and two `H` atoms have equal and opposite bond moments, therefore, net `mu` is zero. 
, Due to `vec(e )`- withdrawing `(-I)` effect of two `Br` atoms and `vec(e )`- donating `(+I)` effect of two `Me` atoms in the same direction, net resultant dipole moment is more. 
, Due to `vec(e )`-withdrawing `(-I)` effect of two `Br` atoms and `vec(e )` donating `(+I)` effect of two `Me` atoms, there is equal and opposite bond moment. Hence net resultant is zero.
