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Sunday, May 24, 2020

Explain C-H bond length of CH4 is longer than C-H bond length of Difloromethan (CH2F2) ?

Explain C-H bond length of CH4 is longer than C-H bond length of Difloromethan (CH2F2)  because according to bent rule more electronegative atoms decreases S-character in hybrid orbitals and the same time P- Character increases as results bond length increases for those hybrid orbital have more electronegative atoms and bond length of other orbitals decrease having less electronegative atom present hence C-H bond length of CH4 is longer than C-H bond length of Difloromethan (CH2F2

Which is more acidic Me3C-OH Or Me3Si-OH and why ?

Me3Si-OH is more acidic than Me3C-OH because after removal of H+ it's negative ions (Me3Si-O-)stabilized by 2pπ—3dπ back bonding. While Me3C-O- is unstable than Me3C-OH.

B-F bond length in BF3 is shorter than B-F bond length in (BF4)- why?

B-F bond length increases when BF3(130 pm) reacts with F- to form (BF4)- [143 pm]. Its due to absence of Back-bonding in (BF4)- hence B-F bond has completely single bond character

Dipole moment of PCl3F2 and P(CH3)3(CF)2 molecules are zero while dipole moment of PCl2F3 and P(CH3)2(CF3)3 are non zero why?

According to bent rule more electronegative atom or group attached those hybrids orbital have minimum S- character.


There is in trigonal bipiramidal (TBP) Geometry we known that axial orbital hare no s-character so F and -CFgroup are attached with equatorial positions.  Hence dipole moment of P(CH3)2(CF3)2  is zero. While in case of PCl2F3 and P(CH3)2(CF)3 molecules one of the F and –CF3 group are also present at equatorial position hence there is net dipole moment.



Dipole moment of PCl2F3 is non zero while dipole moment of PCl3F2 is zero why?

According to bent rule more electronegative atom or group attached those orbital have minimum S- character. There is in Trigonal bipiramidal (TBP) Geometry we known that axial orbital hare no S- character so F atom attached with axial positions only. Hence PCl3F2 has zero dipole moment.