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Sunday, September 26, 2021

What is the misconceptions about resonance?

Many misconceptions are associated with resonance and the same need to be dispelled. 
You should remember that : 
(1) The cannonical forms have no real        existence.
(2)The molecule does not exist for a       certain fraction of time in one     cannonical form and for other       fractions of time in other cannonical       forms.
(3) There is no such  equilibrium between the cannonical forms as we have between tautomeric forms (keto and enol) in tautornerisrn. 
(4) The molecule as such has a single       structure which is the resonance       hybrid of the cannonical forms and       which cannot as such be depicted by     a single Lewis structure.
(5) Resonance is a theoratical concept. The resonating structure have no physical reality, i.e., they do not actually exist. Only the hybrid structure exists. The hybride structure can not be represented on the paper but resonating structure can be represented.

Salicylic acid is a stronger acid than Benzoic acid. Why?

Salicylic acid is a stronger acid than benzoic acid. It is due to the fact that in salicylate ion (conjugate base of salicylic acid) intramolecular H-bond formation takes place which makes the conjugate base more stable.

Related Questions:

1.                 Highly branched carboxylic acids are less acidic than unbranched acids. Explain why?

2.                 Benzamide is less easily hydrolysed than methyl benzoate. Why ?

3.                 Alcohols and Phenols both are acidic but phenols are more acidic. Why?

4.                 Which is more acidic 2-methyl benzoic acid , 3-methyl benzoic acid or 4-methyl benzoic acid.?

5.        Why is o-toluic acid (2-methyl benzoic acid) stronger than benzoic acid ?

6.                 What is the ortho effect? Why are nearly all ortho substitute benzoic acids (except some groups) stronger acid than benzoic acid?

7.                 Name of groups which does not show ortho effect in benzoic acid?

8.                 Why Picric acid (2,4,6-trinitrophenol) is weak acid then expected ?

9.                 What is Steric Inhibition of Deprotonation effect ? Or SID effect ?

10.           Alcohols and Phenols both are acidic but phenols are more acidic. Why?

11.           Among orthochlorophenol and orthofluorophenol, which will be a stronger acid and why?

12.           Why The phenoxide ion is more stable than phenol ?

13.           What is correct acidic strengths order of the haloforms acids ? Give correct explanation.

14.           Lower aliphatic acids having 1 to 5 carbons are soluble in water but higher fatty acids having six or more than six carbon are insoluble in water but soluble in alcohol. Explain.

15.           Phenoxide ion is more stable than an alkaoxide. why?

16.           Why does aqueous sodium bicarbonate solution dissolve carboxylic acids but not phenol though they are also acidic ?



Among I2, ICI, CCl4, PCl3, POCl3, which molecules exhibit dipole moment?

I2 and CCl4 are symmetrical molecule, their dipole moment is zero, while ICl, PCl3 And POCl3    will exhibit dipole moment.


Related Questions:

(1) The Dipole moment of Chloromethane is more than Fluoromethane. Explain.

Among CH3OH, CH4, CF4, CO2 and CH3F, which has the highest dipole moment?

CH4, CF4 (both tetrahedral), and CO2 (linear) are symmetrical molecules. Their dipole moment is zero. Since fluorine is more electronegative than oxygen, the dipole moment of CH3F is higher that of CH3OH. Thus, among CH3OH, CH4 CO2 and CH3F, CH3F has the largest dipole moment.

Related Questions:

(1) The Dipole moment of Chloromethane is more than Fluoromethane. Explain.

Which out of H2+ and H2– molecular ions is more stable and why?

H2 is less stable than H2+ because in H2 one electron is present in anti-bonding molecular orbital.

Related Questions:

(2) What is the temperature at density of water is maximum ?