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Saturday, December 5, 2020

What is the nucleophilicity of halides?

Nucleophilicity of nucleophile is inversely proportional to hydration energy or solvation energy. Fluorine is smallest among hence it highly solvate and more hydration energy ,and hence less nucleophilicity than other halides.

The correct nucleophilicity order is as:
                I- > Br- > Cl- > F-

Calculate radial and angular node for 2p-orbitals.

Radial node in 2p (i.e., l=1)
                  = n-l-1
                  = 2-1-1 =0
Angular node in 2p =l=1

Friday, December 4, 2020

What is Boltzmann's constant?

The Ideal gas law PV=nRT
Where n is number of moles of gas

              n=N/NA
Where N= number of gaseous molecules and NA is Avagadro's  number

            PV=(N/NA)×RT
            PV=N(R/NA)×T
            PV=N(Kb)×T
Where Kb is Boltzmann's constant

 Kb=R/NA= (8.31÷6.022×10^23)
                  = 1.38×10^-23



How to determine acidic strength order of following compounds?


  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 ?
  17. Chloroform is more acidic than fluoroform why?
  18. Fluorine is more electronegative than chlorine even then, p-flurobenzoic acid is weaker acid than p-chlorobenzoic acid explain ?
Related Questions:
  1. Penta-1,3-diene is more stable than penta-1,4 -diene. Why?
  2. Phenoxide ion is more stable than an alkaoxide. why?
  3. Why does aqueous sodium bicarbonate solution dissolve carboxylic acids but not phenol though they are also acidic ?
  4. Why enol form of Beta Dicarbonyl compound more stable than those of monocarbonyl compounds?
  5. Why enol form of phenol is more stable than its keto isomers?
  6. Reactivity order of Pyrrole, Furan and Thiophene towards Electrophilic substitution :
  7. Phenyl group is known to extract negative inductive effect, but each phenyl ring in biphenyl is more reactive than benzene towards Electrophilic substation. Why?
  8. Chloroform is more acidic than fluoroform why?
  9. Fluorine is more electronegative than chlorine even then, p-flurobenzoic acid is weaker acid than p-chlorobenzoic acid explain ? 
  10. Trifluoroethyl carbocation is less stable than trifluromethyl carbocation why ?
  11. Why is the Tropylium carbocation less stable than the tricyclopropylmethyl carbocation?