Question

Notes Sulfuric acid causes chemical burns that can seriously damage skin eyes; avoid contact. he solid t with Clean and number five small test tubes. Add 1 mL of aqueous 0.05% nota sium permanganate to each test tube. Use test tube #1 as a control and add one drop of each of the following alcohols to the other test tubes: methanol: #3, ethanol;#4,2-propanol; #5, 2-methyl-2-propanol. Stopper and shake each test tube for 10 seconds and record your observations immedi ately after shaking, then after standing for 5 and 10 minutes, respectively. To any solution that shows little or no evidence of reaction (compared to the control) after 10 minutes, add 2 drops of 3.0 M HCl, shake, and observe at the same intervals as before. To any solution that shows little or no evidence of reaction 10 minutes after the HCl addition, add 2 drops of concentrated sulfuric acid, shake, and observe at the same intervals as before. Arrange the alcohols in order of reactivity toward KMnO, and de scribe the effect of substrate structure on reactivity. Based on alcohol reac tions you have studied, explain any reaction of a tertiary alcohol for which you saw evidence. Draw the structure of the organic product of each reac tion. Write a balanced equation for the reaction of methanol with acidic KMnO, (you can balance it using the half-reaction method taught in gener al chemistry) potas- lutions mer. Donec

please write out the redox reactions for methanol, ethanol, 2-propanol, and 2-methyl-2-propanol based on this experiment

Answer 1

Note that KMnO4 in acidic medium oxidized primary and secondary alcohols. It does not oxidize tertiary alcohol. So, No reaction with 2-methyl-2-propanol.

Also, Primary alcohols are oxidized to carboxylic acids and Seconadry alcohols are oxidized to ketones.

For balancing the redox reactions, following steps are followed:

Step 1: Identify the reduction and oxidation parts.

Step 2: Balance each part separately.

           i) The change in electrons would be equal to difference in oxidation states.

          ii) Next balance everything else, except H and O

          iii) Balance charge by adding H+

          iv) Balance ), by adding water molecules.

Step 3: Add both the reduction and oxidation half to cancel the total electrons and Simplify.

Kindly see below for balanced equations:

Reduction half will remain same for all the three reactions.

medium, it KMnOy is an oxidizing agent . In acidic reduces to Mn +2 Reduction half: Minou (aq) +5etont - (+7) Mitz + 49 H2O 4) (aq) - (CH₃OH) (1) For methanol Onidation half : (1) (+3) CH₂OH + H₂O u HCOOH + he + 4H+ combining 0 & 2; that is 0x4 + 6 x 5 4mn Ou (aq) at 200 + 324 t + 50H₂OH + 5 H₂O - 4 Mn +2 + 16H₂O + 54cool+ 206+ 204+ simplifying + 440 5CH₂OH (d) 4 Mn Oy lag) at 124 (22) - 11 H₂0 (1) 4mn 27 at 54cooH + (aq) (1) (2) for Ethanol (CH₃ CH₂OH) (0) (+4) Onidation half : CH 01 +4₂0 - CH₂ Coon + Yé tunt (same as in (1) above) combining 0 8 ③ 0 xu + x3 a simplifying u mnou (aq) + 12 HP (aq) + 5CH₃ CH ₂ OH (1) UMP + + 5 chocoon +11901) (+2) un-c-CH₂ +2e +24+ (3) for 2-propanol (340) oxidation half: CH₂-CH-CH₂ (C3H30) Рен eqh (0 x 2 + eq" (4 x 5 & simplifying * 2 MnO4 + 5 C3 MgO + 6H0 → 2 mnt 2 4 8 30 + 5 C3 460

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