Organic Acids and Bases MCQs [Organic Chemistry]

MCQs-based questions and answers on Organic Acids and Bases in organic chemistry.

Which is not a reasonable (strong) nucleophile?

  1. OH
  2. NH3
  3. H2O
  4. CN

Question’s Answer: H2O


Higher basiscity of pyridine than pyrrole is justified by which of the following?

  1. Huckle rule
  2. Hybridization of nitrogen
  3. Electron donating effect on amino group
  4. Both a and b

Question’s Answer: Both a and b


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

  1. Sandmeyer reaction
  2. Witting reaction
  3. Lucas test
  4. Ninhydrin test

Question’s Answer: Lucas test


Inorganic acids (HCl, HBr. HNO, etc.) have Ka value

  1. <10
  2. >1
  3. >10
  4. <1

Question’s Answer: <1


Weak acids have Ka value

  1. <10-1
  2. >10-4
  3. >10-5
  4. <10-5

Question’s Answer: <10-1


Which acid have highest pKa value?

  1. CICH2COOH
  2. CH3COOH
  3. H₂O
  4. FCH2COOH

Question’s Answer: H₂O


Which have high pKa value?

  1. Ammonia
  2. Methylamine
  3. Pyridine
  4. Pyrrole

Question’s Answer: Methylamine


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

  1. Asymmetric effect
  2. Stark effect
  3. Salt effect
  4. Leveling effect

Question’s Answer: Leveling effect


Which statement is true regarding Arrhenius concept?

  1. This concept is applicable only for aqueous systems
  2. Neutralization takes place in aqueous medium only
  3. H ion cannot remain as such in water
  4. This concept is applicable for non-aqueous systems only

Question’s Answer: This concept is applicable for non-aqueous systems only


Which does not represent Lewis base?

  1. BF3
  2. NaNH2
  3. NaOH
  4. Pyridine

Question’s Answer: BF3


Which statement do not represent Lewis idea of acids and bases?

  1. Compounds in which the central atom can expand its octet
  2. Compounds which have incompletely filled orbitals
  3. Compounds which have completely filled orbitals
  4. All simple metal ions like Ag+, Al3+ etc.

Question’s Answer: Compounds which have completely filled orbitals


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

  1. concept has many bases that have OH ions
  2. A base can accept a proton
  3. An acid can donate a proton This
  4. This concept is more general

Question’s Answer: This concept has many bases that have OH ions


Which pairs does not represent Lowery acid-base pair?

  1. H2O + NH3
  2. CH3NH2+ BF3
  3. HCl + H2O
  4. H2O+ H₂O

Question’s Answer: CH3NH2+ BF3


Which does not represent Lewis acid?

  1. ZnCl2
  2. FeCl3
  3. BuLi
  4. BF3

Question’s Answer: BuLi


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

  1. Inductive effect
  2. Resonance effectc
  3. Mesomeric effect
  4. Salt effect

Question’s Answer: Inductive effect


Which groups exert –I effect?

  1. -COOH
  2. -CN
  3. -NO
  4. All A, B, and C

Question’s Answer: All A, B, and C


Which sets consists of only polar aprotic solvents?

  1. DMF, acetonitrile, DMSO
  2. Acetic acid, DMF, toluene
  3. DMSO, ethanol, acetonitrile
  4. Water, hexane, methanol

Question’s Answer: DMF, acetonitrile, DMSO


Why Maleic acid is stronger than, fumeric acid?

  1. Electron donating effect of-COOH.
  2. Electron withdrawing effect of -COOH.
  3. Intramolecular Hydrogen Bonding
  4. All of A, B, and C

Question’s Answer: Intramolecular Hydrogen Bonding


Which groups does not exert +I effect?

  1. S1R3
  2. –COO
  3. >C=0
  4. –CH2Me

Question’s Answer: >C=0


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

  1. Resonance effect
  2. Field effect
  3. Asymmetric effect
  4. Inductive effect

Question’s Answer: Field effect


Which is true order of amine strength in gas phase?

  1. CH3NH2 > NH3 > (CH3)3N > (CH3)2N
  2. (CH3)2NH < (CH3)3N < NH3 > CH3NH2
  3. (CH3)3N < (CH3)2NH > CH3NH2 > NH3
  4. NH3 < CH3NH2 < (CH3)2NH < (CH3)3N

Question’s Answer: NH3 < CH3NH2 < (CH3)2NH < (CH3)3N


Which haloacids is stronger acid?

  1. BrCH2COOH
  2. CICH2COOH
  3. FCH2COOH
  4. ICH2COOH

Question’s Answer: FCH2COOH


Which factors affect the strength of an acid?

  1. Strength of the H-A bond01
  2. The nature of the solvent
  3. Electronegativity of A
  4. All A, B, and C

Question’s Answer: All A, B, and C


HS is stronger acid than H₂O because ______.

  1. H2S is a gas while HO is liquid
  2. S-H bond is weaker than O-H bond
  3. S-H bond is stronger
  4. H2S forms H-bonding

Question’s Answer: S-H bond is weaker than O-H bond


Which factors affect the strengths of acids and bases?

  1. Inductive effect
  2. Hydrogen effect
  3. Resonance effectc
  4. All A, B, and C

Question’s Answer: All A, B, and C


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

  1. Hammett equation
  2. Taft equation
  3. Differential equation
  4. Linear equation

Question’s Answer: Hammett equation


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

  1. It develops a quantitative relationship between structure and reactivity
  2. This equation can be used to calculate the value of pK
  3. This equation does not help to calculate the rate of some reactions
  4. This equation has mechanistic implications
  5. It classifies the substitutes into two categories

Question’s Answer: This equation does not help to calculate the rate of some reactions


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

  1. Only applicable to aliphatic systems
  2. It is only applicable to aromatic systems
  3. It is not valid for m-substituent
  4. It is not valid for p-substituent

Question’s Answer: Only applicable to aliphatic systems


Which equations represent linear free energy relationship?

  1. Hammett equation
  2. Helmholtz equation
  3. Taft equation
  4. Differential equation

Question’s Answer: Taft equation


Which is a nucleophile?

  1. AICI3
  2. CN
  3. BF3
  4. H3O+

Question’s Answer: CN


Which is not a nucleophile?

  1. CN
  2. NH3
  3. CH3O
  4. BF3

Question’s Answer: BF3


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

  1. Nucleophile
  2. Ligand
  3. Ambient nucleophile
  4. None of A, B, and C

Question’s Answer: Ambient nucleophile


Tert-butyl cation is stabilized through which phenomenon.

  1. Resonance effect
  2. Hyperconjugation
  3. Conjugation effect
  4. Mesomeric effect

Question’s Answer: Hyperconjugation


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

  1. CH3OH > CH3CH2OH > (CH3)3COH > (CH3)2CHOH
  2. (CH3)3COH > (CH3)2CHOH > CH3CH2OH > CH3OHc
  3. CH3CH2OH > CH3OH > (CH3)3COH > (CH3)2CHOH
  4. CH3OH > CH3CH2OH > (CH3)2CHOH > (CH3)3COH

Question’s Answer: CH3OH > CH3CH2OH > (CH3)2CHOH > (CH3)3COH


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

  1. (CH3)2NH > CH3NH > NH3 > (CH3)3N
  2. NH3 > CH3NH2 > (CH3)2NH > (CH3)3N
  3. (CH3)2NH > CH3NH2 > (CH3)3N > NH3
  4. CH3NH2 > (CH3)2NH > NH3 > (CH3)3N

Question’s Answer: (CH3)2NH > CH3NH2 > (CH3)3N > NH3

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