1)What is the difference between phenanthrene and anthracene?Their structures are quite similar
2)why are double bonds are stronger and shorter than single bonds?
3)Is the bond angle in methyl anion 109.5.?If so why is it different from that of ammonia(107.3) which also has one non boding pair and three bonding pairs?
71
2. Clearly, While single bonds are formed in the upper two figures of the given picture, there is less (compared to other bonds) net overlapping between the orbitals. However, when there is formed a Double bond which includes a π and σ bond, the p orbitals overlap with more interaction (As you see in the lower two figures of the above figure).
Hence, Double bond is stronger, hence shorter than Single bonds. Again in turn Triple bond is stronger than the Double bond in the similar manner.
71Methyl anion is CH3-.
CH4 - H + e ----> CH3-
Well there is no difference of it with the Ammonia except that the central atoms are different. So for both the angles will be same and even the structure and hybridization too.
711. What is the difference between phenanthrene and anthracene?Their structures are quite similar
Ans: This is what you call isomerism in Chemistry. Antrhacene is a linear isomer of Phenanthrene. To understand the term linear see below:
Anthracene:
Phenanthrene:
113)Is the bond angle in methyl anion 109.5.?If so why is it different from that of ammonia(107.3) which also has one non boding pair and three bonding pairs?
Ammonia has a lone pair of electrons so its bond angle reduces
Yes the bond angle of methyl anion is 109.5, it is tetrahedral and sp3
hydridised. I think here the negative charge on methyl ion stabilizes it.
11It is a well-known fact that among isomers,the stability of benzenoid compounds increases
with the number of Kekulé structures, you question is the example of this, the pair
phenanthrene (possessing 5 Kekulé structures)and anthracene (possessing 4 Kekulé
structures). So the former one is ore stable than latter one.
http://www.mjcce.org.mk/PDF/26_2_375.pdf (download this, you gonna get detail info
about phenanthrene and anthracene)
71@Khyati. Why would the bond angle be different in case of Methyl anion and Ammonia. Both have a non bonding/lone pair of electrons?
"I think here the negative charge on methyl ion stabilizes it."
And how does it do so? Can you please explain how does it happen and other such similar cases so that we might be careful the very next time. I meant examples!!
And probably by the latter explanation, I think you meant that "phenanthrene (possessing 5 Kekulé structures)" is more resonance stabilized than anthracene "(possessing 4 Kekulé structures)".
May you please confirm my interpretation of your answer!!
71Seems Vivek chem bhi padhne laga
Aur iska matlab kya hai. Chemistry 'bhi' ???