See image — Alcohols Phenols and Ethers Chemistry Question

💡 Solution & Explanation

Concept: Periodic acid (HIO4) cleaves vicinal diol (and alpha-hydroxy carbonyl) systems. Each C-C bond between two adjacent hydroxyl-bearing carbons (or between a hydroxyl carbon and a carbonyl carbon) is cleaved. Terminal -CH2OH groups yield formaldehyde (HCHO); internal CHOH groups yield formic acid (HCOOH); ketone/aldehyde carbons adjacent to CHOH yield formic acid or CO2 depending on context, but specifically a ketone flanked by OH groups yields formic acid; terminal CH2OH yields HCHO. Reaction 1 substrate: This is a 6-carbon 2-ketose (fructose-type): CH2OH-CO-CHOH-CHOH-CHOH-CH2OH (carbons 1 through 6). Carbon 1 is CH2OH, Carbon 2 is C=O (ketone), Carbons 3,4,5 each bear OH, Carbon 6 is CH2OH. Periodic acid cleavage analysis for Reaction 1: - Bond C1-C2: C1 is CH2OH adjacent to C=O -> cleavage gives HCHO (from C1) and the remainder. - Bond C2-C3: C2 is C=O adjacent to C3-OH -> cleavage; C2 (ketone flanked on both sides) gives formic acid (HCOOH). - Bond C3-C4: both bear OH -> cleavage; C3 gives HCOOH. - Bond C4-C5: both bear OH -> cleavage; C4 gives HCOOH. - Bond C5-C6: C5 bears OH, C6 is CH2OH -> cleavage; C6 gives HCHO. So from Reaction 1: C1 -> HCHO, C2 -> HCOOH, C3 -> HCOOH, C4 -> HCOOH, C5 -> HCOOH, C6 -> HCHO. Formaldehyde count from Reaction 1 = 2 moles. Reaction 2 substrate: This is a 6-carbon aldose (glucose-type): CHO-CHOH-CHOH-CHOH-CHOH-CH2OH (carbons 1 through 6). Carbon 1 is CHO (aldehyde), Carbons 2,3,4,5 each bear OH, Carbon 6 is CH2OH. Periodic acid cleavage analysis for Reaction 2: - Bond C1-C2: C1 is CHO (aldehyde) adjacent to C2-OH -> cleavage; C1 (aldehyde) gives HCOOH. - Bond C2-C3: both bear OH -> C2 gives HCOOH. - Bond C3-C4: both bear OH -> C3 gives HCOOH. - Bond C4-C5: both bear OH -> C4 gives HCOOH. - Bond C5-C6: C5 bears OH, C6 is CH2OH -> C6 gives HCHO. So from Reaction 2: C1 -> HCOOH, C2 -> HCOOH, C3 -> HCOOH, C4 -> HCOOH, C5 -> HCOOH, C6 -> HCHO. Formaldehyde count from Reaction 2 = 1 mole. Ratio of formaldehyde from Reaction 1 to Reaction 2 = 2 : 1 = 2. Therefore, the correct answer is Ratio of reaction I and II = 2.