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JAMB Chemistry 1986 Question 41

Question 41

Carbohydrates, Proteins and Amines

Which of the following is NOT a correct test for the named organic compound in each case?

  1. A.Butanoic acid solution gives effervescence with Na2CO3 solution
  2. B.Glucose when reacted with Na2CrO4 at 0°C will show immediate discharge of colour
  3. C.When but-2-ene is reacted with dilute solution of KMnO4 the purple colour of KMnO4 is discharged readily even at room temperature.
  4. D.When butan-2-ol is boiled with butanoic acid with a drop of concentrated H2SO4 a sweet smelling liquid is produced.
Show the answer and explanation

Answer: B (Glucose when reacted with Na2CrO4 at 0°C will show immediate discharge of colour)

Explanation

Glucose is not tested this way: it does not instantly discharge the colour of a chromate at 0°C (it is tested with Fehling's or Benedict's solution). The other three are correct tests.