(a)
Interpretation:
Based on the understanding of charge stability, it is to be determined which of the following compounds is expected to have the most similar pKa value to that of formaldehyde.
Concept introduction:
Table 6-1 refers to various compounds and their Ka and pKa values. Based on the structural similarities in compounds listed in Table 6-1 and their
(b)
Interpretation:
The pKa value for formaldehyde is to be estimated based on the concept of charge stability and the reference to Table 6.1.
Concept introduction:
pKa value represents the strength of an acid. The lower the value, the stronger the acid. Structural similarity in conjugate bases of two compounds indicates that the pKa values for the two compounds must be in the similar range. The chemical behavior of a compound is governed by the functional group it possesses.
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Organic Chemistry: Principles And Mechanisms: Study Guide/solutions Manual (second)
- 29) Consider the following acid-base reaction: он Cно Na A | в pK, =7 (a) Provide structures for A and B (including nonbonding electron pairs and formal charges where necessary), where A is the conjugate acid and B is the conjugate base of the reaction. Answer: (b) Provide and arrow pushing mechanism to show how A and B are formed. Answer: (c) Will the reaction proceed from left to right (i.e. are A and B favoured at equilibrium)? Explain your answer. Answer: (d) Draw all important resonance contributors of the conjugate base B. Rank the contributors from most stable to least stable (if contributors are equally stable indicate this with an equals sign) most stable leaststablearrow_forwardBr OH H₂O HO (14 pts) Provide a complete mechanism for the reaction in the box. Include all electron-pushing arrows, lone pairs, and formal charges. HO blo NO (S)arrow_forwardWhich of the following bases are strong enough to deprotonate CH,CH,CH,C=CH (pK, 25), so that equilibrium favors the products? CH3CH,Li CH3ONA NH3 O H,0 CH;NHNA ONACH,(CO)N(CH3),arrow_forward
- N-Nitrosamines by themselves are not significant carcinogens. However, they are activated in the liver by a class of iron-containing enzymes (members of the cytochrome P-450 family). Activation involves the oxidation of a C-H bond next to the amine nitrogen to a C-OH group. OH ОН N=0 N=O Og 'N- H+ H N,+ cyt P-450 N-Nitroso- 2-Нydroxy-N- nitrosopiperidine An alkyl diazonium ion piperidine (a carcinogen) Show how this hydroxylation product can be transformed into an alkyl diazonium ion, an active alkylating agent and therefore a carcinogen, in the presence of an acid catalyst.arrow_forward4. Predict the major product of the following reactions. NBS (a) 0°C Na,Cr,07 H,SO, H,0 (b) он H,SO4 CH,OH (d) heat Brarrow_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_forward
- The following Wittig reactions may produce a mixture of alkene stereoisomers. Write the products for each of the reactions and indicate the stereoisomers if any. || Ph,P CH3 + ? (1) LOME (2) R N. Ph,P=CH,R' Mearrow_forwardUsing curved arrow formalism, give the mechanism for the following reaction. Be sure to include important resonance structures, where appropriate. H;C- HgSO4 Н,С- CEC-H Н,с H,SO4, H,0 Н,с сн,arrow_forwardHO CH30 Na A + B O,N pK =7 (a) Provide structures for A and B (including nonbonding electron pairs and formal charges where necessary), where A is the conjugate acid and B is the conjugate base of the reaction. Answer: (b) Provide and arrow pushing mechanism to show how A and B are formed. Answer: (c) Will the reaction proceed from left to right (i.e. are A and B favoured at equilibrium)? Explain your answer. Answer: (d) Draw all important resonance contributors of the conjugate base B. Rank the contributors from most stable to least stable (if contributors are equally stable indicate this with an equals sign)arrow_forward
- (b) Predict the suitable solvent (H2O or CH3COCH3) to increase the reaction of bromopropane(CH3CH2CH2Br) with sodium hydroxide (NaOH). Two reactions are shown below:arrow_forward20. Identify the product for each step in the following reaction sequence. Write complete equations showing the structure of all reactants and products for each step. (a) Isopropyl benzene + NBS/heat ---------->A (b) A+ t-BuOK ---------> B (c) B + 1)BH3 followed by 2)H2O2/NaOH -----> C (d) C + PCC ------> Darrow_forward4. Protonation of alcohol A and subsequent loss of water, produces the intermediate B. CH3 CH; CH, CH, — с — сH, CH, CH;CH, - C- CH, CH; | OH A B (a) (i) Name alcohol A. (11) What type of species is intermediate B? (iii) Draw the structures of the two alkenes which can be formed from species B by removal of a proton. Label as C the alkene which shows geometrical isomerism. (b) The intermediate B is readily attacked by nucleophiles such as water. What is the essential feature of a nucleophile? (c) State what final colour you would see if alcohol A were warmed with acidified potassium dichromate(VI). Explain your answer. Colour Explanation . (ii) Draw two structural isomers of alcohol A which form branched chain ketones when heated with acidified potassium dichromate(VI), but which could not form alkene C on dehydration.arrow_forward