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Organic Acids and Bases MCQs [Organic Chemistry]

1. : Which is not a reasonable (strong) nucleophile?

(A) OH–


(B) NH3


(C) H2O


(D) CN–



2. : Higher basicity of pyridine than pyrrole is justified by which of the following?

(A) Hückel rule


(B) Hybridization of nitrogen


(C) Electron donating effect on amino group


(D) Both a and b



3. : To distinguish among primary, secondary and tertiary alcohol, one would use the following experimental method:

(A) Sandmeyer reaction


(B) Witting reaction


(C) Lucas test


(D) Ninhydrin test



4. : Inorganic acids (HCl, HBr, HNO3, etc.) have Ka value

(A) <10


1″ onclick=”checkAnswer(‘q4’, ‘<1')"> (B) >1


10″ onclick=”checkAnswer(‘q4’, ‘<1')"> (C) >10


(D) <1



5. : Weak acids have Ka value

(A) <10⁻¹


10⁻⁴” onclick=”checkAnswer(‘q5’, ‘<10⁻¹')"> (B) >10⁻⁴


10⁻⁵” onclick=”checkAnswer(‘q5’, ‘<10⁻¹')"> (C) >10⁻⁵


(D) <10⁻⁵



6. : Which acid has the highest pKa value?

(A) ClCH2COOH


(B) CH3COOH


(C) H₂O


(D) FCH2COOH



7. : Which have high pKa value?

(A) Ammonia


(B) Methylamine


(C) Pyridine


(D) Pyrrole



8. : It has been observed that all the strong acids show same strength in the aqueous medium. This is known as __.

(A) Asymmetric effect


(B) Stark effect


(C) Salt effect


(D) Leveling effect



9. : Which statement is true regarding Arrhenius concept?

(A) This concept is applicable only for aqueous systems


(B) Neutralization takes place in aqueous medium only


(C) H⁺ ion cannot remain as such in water


(D) This concept is applicable for non-aqueous systems only



10. : Which does not represent Lewis base?

(A) BF3


(B) NaNH2


(C) NaOH


(D) Pyridine



11. : Which statement does not represent Lewis idea of acids and bases?

(A) Compounds in which the central atom can expand its octet


(B) Compounds which have incompletely filled orbitals


(C) Compounds which have completely filled orbitals


(D) All simple metal ions like Ag⁺, Al³⁺ etc.



12. : Which statement is not true with the concept of Bronsted concept of acids and bases?

(A) Concept has many bases that have OH ions


(B) A base can accept a proton


(C) An acid can donate a proton


(D) This concept is more general



13. : Which pairs do not represent Lowery acid-base pair?

(A) H2O + NH3


(B) CH3NH2 + BF3


(C) HCl + H2O


(D) H2O + H2O



14. : Which does not represent Lewis acid?

(A) ZnCl2


(B) FeCl3


(C) BuLi


(D) BF3



15. : The polarization in one sigma bond caused by the polarization of an adjacent sigma bond is known as __.

(A) Inductive effect


(B) Resonance effect


(C) Mesomeric effect


(D) Salt effect



16. : Which groups exert –I effect?

(A) –COOH


(B) –CN


(C) –NO


(D) All A, B, and C



17. : Which sets consist of only polar aprotic solvents?

(A) DMF, acetonitrile, DMSO


(B) Acetic acid, DMF, toluene


(C) DMSO, ethanol, acetonitrile


(D) Water, hexane, methanol



18. : Why Maleic acid is stronger than fumaric acid?

(A) Electron donating effect of -COOH


(B) Electron withdrawing effect of -COOH


(C) Intramolecular Hydrogen Bonding


(D) All of A, B, and C



19. : Which groups do not exert +I effect?

C=O’)”> (A) SiR3


C=O’)”> (B) –COO–


C=O” onclick=”checkAnswer(‘q19’, ‘>C=O’)”> (C) >C=O


C=O’)”> (D) –CH2Me



20. : The effect that operates not through bonds, but directly through space is known as __?

(A) Resonance effect


(B) Field effect


(C) Asymmetric effect


(D) Inductive effect



21. : Which is true order of amine strength in gas phase?

NH3 > (CH3)3N > (CH3)2N” onclick=”checkAnswer(‘q21’, ‘NH3 < CH3NH2 < (CH3)2NH < (CH3)3N')"> (A) CH3NH2 > NH3 > (CH3)3N > (CH3)2N


CH3NH2″ onclick=”checkAnswer(‘q21’, ‘NH3 < CH3NH2 < (CH3)2NH < (CH3)3N')"> (B) (CH3)2NH < (CH3)3N < NH3 > CH3NH2


CH3NH2 > NH3″ onclick=”checkAnswer(‘q21’, ‘NH3 < CH3NH2 < (CH3)2NH < (CH3)3N')"> (C) (CH3)3N < (CH3)2NH > CH3NH2 > NH3


(D) NH3 < CH3NH2 < (CH3)2NH < (CH3)3N



22. : Which haloacid is stronger acid?

(A) BrCH2COOH


(B) CICH2COOH


(C) FCH2COOH


(D) ICH2COOH



23. : Which factors affect the strength of an acid?

(A) Strength of the H-A bond


(B) The nature of the solvent


(C) Electronegativity of A


(D) All A, B, and C



24. : H2S is stronger acid than H2O because ______.

(A) H2S is a gas while H2O is liquid


(B) S-H bond is weaker than O-H bond


(C) S-H bond is stronger


(D) H2S forms H-bonding



25. : Which factors affect the strengths of acids and bases?

(A) Inductive effect


(B) Hydrogen effect


(C) Resonance effect


(D) All A, B, and C



26. : The equation which relates the reaction rates and equilibrium constants of many reactions is known as

(A) Hammett equation


(B) Taft equation


(C) Differential equation


(D) Linear equation



27. : Which statement is not true with respect to applications of Hammett equations?

(A) It develops a quantitative relationship between structure and reactivity


(B) This equation can be used to calculate the value of pK


(C) This equation does not help to calculate the rate of some reactions


(D) This equation has mechanistic implications



28. : Which statement is not true with respect to limitations of Hammett equation?

(A) Only applicable to aliphatic systems


(B) It is only applicable to aromatic systems


(C) It is not valid for m-substituent


(D) It is not valid for p-substituent



29. : Which equations represent linear free energy relationship?

(A) Hammett equation


(B) Helmholtz equation


(C) Taft equation


(D) Differential equation



30. : Which is a nucleophile?

(A) AlCl3


(B) CN–


(C) BF3


(D) H3O+



31. : Which is not a nucleophile?

(A) CN–


(B) NH3


(C) CH3O–


(D) BF3



32. : Compounds that have more than one electron pair on different atoms and may donate to carbon in substrate are known as __.

(A) Nucleophile


(B) Ligand


(C) Ambient nucleophile


(D) None of A, B, and C



33. : Tert-butyl cation is stabilized through which phenomenon?

(A) Resonance effect


(B) Hyperconjugation


(C) Conjugation effect


(D) Mesomeric effect



34. : In solutions, the acidity of simple alcohols is in the order?

CH3CH2OH > (CH3)3COH > (CH3)2CHOH” onclick=”checkAnswer(‘q34’, ‘CH3OH > CH3CH2OH > (CH3)2CHOH > (CH3)3COH’)”> (A) CH3OH > CH3CH2OH > (CH3)3COH > (CH3)2CHOH


(CH3)2CHOH > CH3CH2OH > CH3OH” onclick=”checkAnswer(‘q34’, ‘CH3OH > CH3CH2OH > (CH3)2CHOH > (CH3)3COH’)”> (B) (CH3)3COH > (CH3)2CHOH > CH3CH2OH > CH3OH


CH3OH > (CH3)3COH > (CH3)2CHOH” onclick=”checkAnswer(‘q34’, ‘CH3OH > CH3CH2OH > (CH3)2CHOH > (CH3)3COH’)”> (C) CH3CH2OH > CH3OH > (CH3)3COH > (CH3)2CHOH


CH3CH2OH > (CH3)2CHOH > (CH3)3COH” onclick=”checkAnswer(‘q34’, ‘CH3OH > CH3CH2OH > (CH3)2CHOH > (CH3)3COH’)”> (D) CH3OH > CH3CH2OH > (CH3)2CHOH > (CH3)3COH



35. : In aqueous medium, ______ is the order of amine strength.

CH3NH2 > NH3 > (CH3)3N” onclick=”checkAnswer(‘q35’, ‘(CH3)2NH > CH3NH2 > (CH3)3N > NH3’)”> (A) (CH3)2NH > CH3NH2 > NH3 > (CH3)3N


CH3NH2 > (CH3)2NH > (CH3)3N” onclick=”checkAnswer(‘q35’, ‘(CH3)2NH > CH3NH2 > (CH3)3N > NH3’)”> (B) NH3 > CH3NH2 > (CH3)2NH > (CH3)3N


CH3NH2 > (CH3)3N > NH3″ onclick=”checkAnswer(‘q35’, ‘(CH3)2NH > CH3NH2 > (CH3)3N > NH3’)”> (C) (CH3)2NH > CH3NH2 > (CH3)3N > NH3


(CH3)2NH > NH3 > (CH3)3N” onclick=”checkAnswer(‘q35’, ‘(CH3)2NH > CH3NH2 > (CH3)3N > NH3’)”> (D) CH3NH2 > (CH3)2NH > NH3 > (CH3)3N



 

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