Question

1. [8 Marks The experimentally obtained rate law for the iodine-catalyzed decomposition of acetaldehyde is: R =k[2] [CH CHO (a) Can the following mechanism be used to explain the kinetics of this reaction? Show all your work and justify whenever necessary. Intermediates: I HI, CHOCO, CHE ki 121 Catalyst : Is 1 + CHỊCHO + H + CHICO CH,CO CH3 + CO CH + HÍ - CHI + 1 ki 21 + 1 CHu + co CH₂ CHO 2. [7 Marks Focusing on the electrophilic aromatic substitution (EAS) reaction of benzaldehyde with an electrophile, answer the following questions: (a) Is-CHO an activating or a deactivating substituent? Explain your choice and explain what this classification means when discussing the EAS reaction. (b) Explain, using resonance structures related to the arenium ion, the orientation effects of this substituent.

Answer 1

J, K, 11 — 0 It cмясно, ни + свъto -t3) Chzo kg, c, rco (3) Cuạt MI ký, cutl -7 1 К-, c, rce 9 Rate of rexn d [City] на", 4, [с] [на] - 6 Applying steady state on I - а) - 24115) - L[3] [смус to] +4 Tew3) Lun]-24-1 [2]. = 0 -6 Applying steady state on #2 dча), о= k [1] [che wo1 - Гели3) Luz] - hee'd'ra Ster Strik m см, со d esco9 = [1] [см, о] - Ісусо) -G Applying steady state on cits 4 . 51cuses] - [s][1] (0) [сөз) фи (2) = 21.,Lu) : L11(Е. [35]12 (M from @ & вс, 2412) The my -

id[CM) 2u2 X JE, [12]? [Cles et ] It = d[cky72 dt K [12] 2 [CH₃C Ho] . So above mechanism can be used. 2 @ - CHO is a deactiviring Explanation moving group. Thus ring -Cto draws electron & deactivades it density from the towards bedrophile substitution.

meta directing group. to is Meira as a attood Prentom ion Orto ataell Stop D - Unstabu) Brender ton Repulsion Meta atoel Para Attack Tort CT Repuision une 11 E 4 E14 Arendom ion O=et 11 Areniom son origantes from olf attack unstable due to controlution of len stable () resonating Structure Meta attach toyoured. 7-cro meta directing,