Click an option to check it. The printed options are drawn as a chair plus a furanose; they are redrawn here as Haworth projections carrying exactly the same stereochemistry, with hydrogens omitted for clarity. All four printed options agree on the α-linkage — the two things they disagree about are the C4 chlorine and the fructose anomeric centre.
The paper gives D-galactose as a Fischer projection, so the first job is to read it. The rule for a D-aldohexose drawn with the ring oxygen at the back-right and C1 on the right: a group on the right in Fischer points down in Haworth, a group on the left points up, and C6 always ends up. Click a carbon in the Fischer projection — or step through them — and watch where its OH lands.
Three independent stereochemical decisions turn "a galactose plus a fructose" into one specific molecule. Set each one and the builder draws the result, checks it against the target named in the question, and tells you which printed option you have just drawn.
Hydrogens omitted. The α/β labels mark the two anomeric carbons.
Each printed option is one combination of the two contested decisions. Score all four against the two requirements the question states in words, and exactly one survives.
Note that no option can be eliminated by counting atoms — all four are C12H19Cl3O8 and all four are stereoisomers of one another. The question is purely about configuration.
Sucralose is sucrose with three specific hydroxyls swapped for chlorine and one centre inverted along the way. Those changes stop the body's enzymes from recognising it, so it passes through largely unmetabolised while binding the sweet receptor far more tightly than sucrose does.
| Position | Sucrose | Sucralose |
|---|---|---|
| Pyranose C4 | OH, gluco (equatorial) | Cl, galacto (axial) |
| Furanose C1′ | CH2OH | CH2Cl |
| Furanose C6′ | CH2OH | CH2Cl |
| Glycosidic linkage | α-1↔2′ β | α-1↔2′ β (unchanged) |
| Formula | C12H22O11 | C12H19Cl3O8 |
Replacing the C4 hydroxyl by chlorine with inversion is exactly what turns the gluco configuration of sucrose into the galacto configuration named in the question — which is why the paper says galactose, not glucose.
Sweetness relative to sucrose (= 1), on a logarithmic axis because the values span three orders of magnitude. Values are the commonly quoted mid-range figures; perceived sweetness depends on concentration and formulation.
4-chloro-4-deoxy-α-D-galactopyranose joined to 1,6-dichloro-1,6-dideoxy-β-D-fructofuranose is sucralose, C12H19Cl3O8 — the sweetener sold as Splenda. Nothing else needs to be recalled; the name in the question fully specifies the structure.
The paper's Fischer projection has OH on the right at C2 and C5, and on the left at C3 and C4. Converting for a D-sugar (right → down, left → up, C6 up):
That axial C4 is the single thing distinguishing galactose from glucose. Replacing it by chlorine keeps the position: the C4 chlorine must point up. This eliminates (B) and (C), which draw it equatorial.
"α-D-galactose" means the C1 substituent — here the glycosidic oxygen — points down in the standard Haworth orientation, trans to the C6 branch. All four printed options draw this correctly, so it eliminates nothing, but getting it wrong would not give sucralose.
"β-D-fructofuranose" fixes the configuration at C2′. In the orientation the paper uses, that puts the C1′ CH2Cl up and the glycosidic oxygen down. Options (C) and (D) draw the CH2Cl down — the α anomer — so they go.
Answer: (A).
BAQAVOSOZGMPRM-QBMZZYIRSA-N).CO[C@H]1O[C@H](CO)[C@H](Cl)[C@H](O)[C@H]1O, identical to the galactose half of the
reference; the equatorial build differs at exactly one stereocentre. So (B) and (C) are
demonstrably the gluco isomer.CO[C@]1(CCl)O[C@H](CCl)[C@@H](O)[C@@H]1O, identical to the reference; the
CH2Cl-down build is its C2′ epimer. So (C) and (D) are the α-fructofuranoside.| Simulation ID | ADV-2026-P2-CHE-Q04 |
| Exam / Year / Paper | JEE Advanced · 2026 · Paper 2 |
| Subject | Chemistry (Organic / Biomolecules) |
| Chapter | Biomolecules |
| Topic | Carbohydrates — structure and glycosidic linkages |
| Subtopics | Fischer and Haworth projections · Anomers and the α/β convention · Epimers (glucose vs galactose) · Pyranose and furanose rings · Glycosidic linkage in a non-reducing disaccharide · Deoxy-halo sugars · Artificial sweeteners |
| Question type | Single correct MCQ (+3 / 0 / −1) |
| Difficulty | Moderate |
| Answer | (A) sucralose |