Concept explainers
Interpretation:
The given compounds L-P are to be ranked in order of decreasing acid strength, from lowest pKa to highest pKa.
Concept introduction:
The strength of an acid depends on the stability of conjugate anion (base) formed by the removal of the acidic proton. The stronger acid has higher the stability of the conjugate base. The stronger the acid, the higher is its
In case of organic compounds, the stability of the conjugate base depends on several factors - the electronegativity of the atom(s) that bears the negative charge, resonance delocalization of the negative charge, and hybridization of the atom that bears the negative charge.
The stability of the conjugate base increases with increasing electronegativity of the atom that bears the charge, increasing number of atoms over which the charge is delocalized, and finally, increasing s orbital character of the atom that bears the charge. In cyclic compounds with a conjugated
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Chapter 14 Solutions
ORGANIC CHEMISTRY SG/SM PA +SQUARECAP E
- Rank the following ammonium ions in order of increasing pKa.arrow_forwardWhich of the compounds shown below is the most acidic hydrogen and what is the approximate pKa value?arrow_forwardThe pKa for Molecule A is 10 units lower than Molecule B. Molecule A Draw conjugate base of A :B H H pKa = 10 Molecule B Draw conjugate base of B OCH3 :B H H pКa 3 20 Please provide a brief explanation for the difference in pKa of these to molecules.arrow_forward
- (i) Draw the dissociation reaction for a carboxylic acid in water and define the Ka for this reaction. Write the equation that relates pKa to Ka. (ii) A deprotonated carboxylic acid can be drawn in two resonance forms. Draw the two forms and explain what the term “resonance” means. (iii) Draw an energy profile for the above dissociation reaction and describe how the profiles for a strong and a weak acid would differ.arrow_forwardThe higher the pK, value the weaker the acid. True Falsearrow_forwardRank the following molecules according their acidity. (1 = lowest pka) OEt O 요 ii iiNet il 요 NEt₂ O O CF 3 Predict how the highest pka from question 9 compares with the lowest pka from question 8.arrow_forward
- Name the following molecules, then rank their basicities in decreasing order (1 = most basic, 3 = least basic).arrow_forwardPregabalin, C3H17NO2 is used as a treatment of epilepsy and neuropathic pain. NH2 pK, = 4.2 %3D H. pK = HO, = 3.4 Select the equilibrium corresponding the to the pK, = 9.8 CgH18NO2 (aq) + H20 (I) C3H17NO2 (aq) + OH (aq) C3H16NO2 (aq) + H20 (1) CgH17NO2 (aq) + OH (aq) CgH17NO2 (aq) + H20 (1) C3H18NO2 *(aq) + OH (aq) C3H17NO2 (aq) + H20 (1) CgH16NO2 (aq)+ H30*(aq)arrow_forwardFrom each pair, select the stronger base. Then draw the conjugate acid of the strong base below. CH3CH20 or CH3CEC • You do not have to consider stereochemistry. You do not have to explicitly draw H atoms. • You do not have to include lone pairs in your answer. C opy astearrow_forward
- Arrange the compounds in each set in order of increasing acid strength. consult Table 4.1 for pKa values of each acid.arrow_forward3. Which is the stronger acid: (a) Benzoic acid with a Ka of 6.5 x10-5 or hydrocyanic acid with a Ka of 4.9 x 10-10? (b) Boric acid with a pKa of 9.14 or carbonic acid with a pKa of 6.37arrow_forwardTwo pk, values are reported for malonic acid, a compound with two COOH groups. Explain why one pk, is lower and one pk, is higher than the pKa of acetic acid (CH;COOH, pKg = 4.8). ple HO malonic acid HO, Но pk = 2.86 pk = 5.70arrow_forward
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