Related InterviewSolutions

• Reimer-Tiemann reaction introduces an aldehyde group on to the aromatic ring of phenol, ortho to the hydroxyl group. This reacrtion involves electrophilic aromatic subsititution. It is a general method for the synthesis of subsituted salicyladehydes as depiced below: Which one of the following reagents is used in the above reaction ?A. aq. `NaOH+CH_(3)Cl`B. aq. `NaOH+CH_(2)Cl_(2)`C. aq. `NaOH+CHCl_(3)`D. aq. `NaOH+C Cl_(4)`
• Reimer Tiemann reaction introduces an aldehyde group, on to the ring of phenol, ortho to hydroxyl group. The reaction involves electro-philic aromatic substitution. This is a general method for synthesis of substituted salicyladehyde as depicted below Which one of the following reagents is used in the above reactionsA. aq `NaOH+CH_(3)Cl`B. aq `NaOH+CH_(2)Cl_(2)`C. aq `NaOH+CH_(3)Cl_(3)`D. aq `NaOH+C Cl_(4)`
• Both alcohols and phenols contain a hydroxyl group, but phenols are more acidic than alcohols. The reason being that the phenoxide ion left after the removal of a proton is resonance stabilized while alkoxide is not. Therefore, phenols dissolve in aqueous sodium hydroxide but alcohols do not. However, both are weaker acids than carbonic acid and hence do not decompose aqueous `NaHCO_(3)` solution evolving `CO_(2)`. The presence of electron-donating groups in the benzene ring decrease the acid strength while the presence of electron withdrawing groups in the benzene ring increase the acid strength of phenols. The relative strength of o-, m- and p- substituted phenols, however, depends upon a combination of inductive and resonance effects of the substituent. Alcohols are very weak acids even weaker than water. Because of the `+I` effect of the alkyl groups, tha acidic strength of alcohols decreases in the order : `1^(@)` alcohol `gt 2^(@)` alcohol `gt 3^(@)` alcohol. Which of the following is the strongest acidA. `FCH_(2)CH_(2)CH_(2)OH`B. `FCH_(2)CH_(2)CH_(2)OH`C. `CH_(3)CH_(2)CHFCH_(2)OH`D. `CH_(3)CH_(2)CF_(2)CH_(2)OH`
• Which one of the following compounds has the most acidic nature?A. B. C. D.
• How will you explain that phenols are acidic in nature ?
• Which of the following orders is true regarding the acidic nature of phenols ?A. Phenol `gt` o-cresol `lt` o-nitrophenolB. o-cresol `lt` phenol `lt` o-nitrophenolC. Phenol `lt` o-nitrophenol `lt` o-cresolD. o-nitrophenol `lt` o-cresol `lt` phenol
• Which one of the following compounds has the most acidic nature?A. B. C. D.
• Which one of the following is most reactive towards electrophilic reagent ?A. B. C. D.
• Assertion : Phenol is acidic in nature. Reason : Hydrid for phenate ion is less resonance stabilised than hybrid for phenol.A. If both assertion and reason are correct and reason is correct explanation for assertion.B. If both assertion and reason are correct but reason is not correct explanation for assertion.C. If assertion is correct but reason is incorrect.D. If assertion and reason both are incorrect.
• The best reagent to covert pent-3-en-2-ol into pent-3-en-2-one is :A. acidic permanganateB. acidic dichromateC. chromic anhydride in glacial acetic acidD. pyridine chlorochromate.