1. Rank the alanes below in order of increasing relative Lewis acidity (1 is most acidic, 4 is least acidic). Provide a brief explanation for your ordering. AlCl3 Al(Et)3 Rank: AICI(Et)2 AlCl2(Et)

Pyridine forms a stronger Lewis acid-base complex with SO3 than SO2. However, pyridine forms a weaker complex with SF6 than with SF4. Explain the difference.

Aniline (conjugate acid pKa 4.63) is a considerably stronger base than diphenylamine (pKa 0.79). Account for these marked differences.

Help!

(a) Rank the following compounds in order of increasing acidity. (b) Which compound forms the strongest conjugate base?

As far back as the 16th century, South American Incas chewed the leaves of the coca bush, Erythroxylon coca, to combat fatigue. Chemical studies of Erythroxylon coca by Friedrich Wöhler in 1862 resulted in the discovery of cocaine, C17H21NO4, as the active component. Basic hydrolysis of cocaine leads to methanol, benzoic acid, and another compound called ecgonine, C9H15NO3. Oxidation of ecgonine with CrO3 yields a keto acid that readily loses CO2 on heating, giving tropinone. (a) What is a likely structure for the keto acid? (b) What is a likely structure for ecgonine, neglecting stereochemistry? (c) What is a likely structure for cocaine, neglecting stereochemistry?

The pKa, of the conjugate acid of morpholine is 8.33. (a) Calculate the ratio of morpholine to morpholinium ion in aqueous solution at pH 7.0. (b) At what pH are the concentrations of morpholine and morpholinium ion equal?

The gas-phase basicity of triphenylamine (876.4 kJ mol-1) is less thanthat of triphenylphosphine (940.4 kJ mol-1). Write an equation torepresent each reaction. Do you expect electronic or steric factors tocontribute more to this difference? Explain

The table shows the base ionisation constant, Kb, for several selected compounds. (a) Compound C6H5NH2 Kb 3.8x10-10 1.7x10-6 N2H4 NH3 1.8x10-5 NH2OH 1.1x10-8 i. Arrange the compounds in order of increasing strength of base. ii. Give the structure of conjugate acid for each compound and arrange them in order of increasing strength of acid. (b) The percentage ionisation of 0.010 M NH3 solution was 4.2 % ionisation. Calculate Kb. 1.8x105

(a) Tsomane and Nyiko were given a task of synthesising methylenecyclohexane 2. After a brief discussion with each other, Tsomane proposed Method A to synthesise 2 from cyclohexanone 1 while Nyiko proposed Method B that started from hydroxymethylcyclohexane 3. Each student believed that their proposed method is better than the other. (Scheme below) (1) Ph Ph 836 Ph THF A 1 B H₂SO4 100 °C 3 OH Which of the two methods (A or B) is more likely give high yield of methylenecyclohexane 2? Briefly explain.