1.) the nodal plane in the pi bond of ethane is located in
a) the molecular plane
b) a plane perpendicular to the mol plane wich bisects the C-C σ-bond at right angle
c) a plane parallel to mol plane
d) a plane perpendicular to the mol plane wich contains the C-C σ-bond at right angle
2.)the strongest bond is...
a) C-C
b) C-H
c) C-N
d) C-O
(give reasons for ur answers..)
1c-H=107
c-N=138
c-o 121
c-c=154
these are bond lengths in pm.
so strongest bond is C-H............:)
1isn't that for the determination of covalent character of ionic compounds? Fajan's rules I mean
1but could u xplian what u meant by small cation . more polarisation??
In CH , H is more electro positive and it is the cation. ( In other C is the cation ).
In this case, H is small compared to C in other cases ..
And by fajans rule, smaller cation = more polarization power and more covalent character .. and covalent is stronger than Ionic right ?
33Oh!! Chemistry........
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1I'll accept that only under the condition that the cleavage of bondis to be initiated by heating .
33"CH bond is definitely more polar than CC .thus undergoes cleavage easier than CC . hope It's clear.-Srinath"
But the discussion was that CH is strongest....thats the answer sky gave as in her soln...
1your Fajan's rule seems fine , but could u xplian what u meant by small cation . more polarisation??and why CH seems stronger unable to get ur poinit
1CH bond is definitely more polar than CC .thus undergoes cleavage easier than CC . hope It's clear.
You mean CC bond is stronger ?
Also, according to fajans rule, small cation = more polarisation and more covalent... So CH is stronger ..
And in other options, C is cation right ? ( more positive)
1ok , atlast I think I've foud a convincing answer.
All these bond dissociation energies that are mentioned refer to breaking of bonds by the action of heat. i.e. thermal cleavage. but , In the reaction medium , more important is the polarity of the bond. CH bond is definitely more polar than CC .thus undergoes cleavage easier than CC . hope It's clear.
1aren't we supposed to consideronly single bonds b/w the atoms? I don't think it's fair considering a double bond for one and triple bond for another , bcoz sky's Q asks only for the single bond energy I bleieve. double and triple bonds are obviously stronger.
33i also thought the reasons(see my first two posts in this topic) for C-N and C-O bonds it worked gud for C-N but not that gud for C-O...
Oh this is bad about chem. experimental and theoritical beliefs always contradict.
1oops , I didn't know that , thankx . I thought bonding b/w like atoms produces the strongest bond.
but I'm abit confused. In Bayer villiger oxdn , it's easier to convert aldehyde to acid than a ketone to an ester . so I thought C-C is more storng.
33Srinath just see the general chemistry forum :
Forum » General Chemistry » Some reference datas........
can u xpalin the experimental result that C-H bond energy > C-C so how u r saying C-C is strongest...
33This is experimental proof any one got anything thing theoratical........
1nodal plane is the plane where probability of finding an electron is zero.
so b and c shouled not bhee answer
2nd part all these are single bond?
33No but in NCERT(Chem part II edtn nov 2007,page 293, Example 10.5) also is written C-C bond is more stable than C-N and
for C-O bond the nucleophilcity of CN and OH??
1PHEW!!!!!!!! ALL MY FLOP CONCEPTS NOT WORKING....
......btw y dun we go by bond order as nishant bhaiya told???
C-O = 3
C-N=2.5
C-C =2
C-H =0.5
33on pauling scale....
Electronegativity diff of
CN = .49
CO= .9
CH= .34
1now ..............
most surpringly..........
C-H is most strongest........(the ans given)
i can think of only one explanation for this......i.e. electronegative diff btwn C n H is highest mong the four so more ionic character ....... n so, stronger bong .......
comment.....
33I think that should also be true for C-C and C-N bond as -CN is formed more favourably thab -NC> When CN- is present and due to rresonance it can attack via N or C but it generally by C so.......
Also C-N and C-O bond has almost same properties as C=O and C=N has almost same rkns...
So C-C bond strength>C-N
also C-C bond strength>C-O
but don't know about comparison b/w C-O and C-N
for C-H bond i think its weaker because its C-H bond aur jaha thoda acidic H hota ha,i bond toot jata hai.......
33We have got only bond orders of molecules having same atom...
but i know one thing C-C bond is stronger than C-O bond thats why CN- is stronger nucleophile than OH- although a weker base than OH-
62On a second thought..
why dont u try finding bond order for these ?
I think that could/should help
1bond strength should it not depend overlap of atomic orbitals of the bonds?
I think that should help.. but i have not found any answer :(
this is easy but i am bad.