Step 1: Glucose is indeed an aldohexose (6-carbon sugar with an aldehyde group) — true.
Step 2: Glucose does exist predominantly in the cyclic pyranose (6-membered ring) form in solution — true. It also gives a positive 2,4-DNP test (confirming the carbonyl group) — true.
Step 3: Heating glucose with HI does not simply give n-hexane under mild/normal heating — this specific product (n-hexane) requires prolonged/repeated reaction with HI (a much more extensive/vigorous reduction), not just 'heating'. As commonly tested, this statement (implying simple heating suffices) is the one that is NOT straightforwardly true as phrased, making it the exception among otherwise-true statements about glucose.
Correct option: (b) On heating with HI it forms n-hexane.
