Biomolecules · Question 34

Given below are two statements: In the light of the above statements, choose the correct answer from the options given below

1. Statement I is true but Statement II is false
2. Both Statement I and Statement II are true
3. Statement I is false but Statement II is true
4. Both Statement I and Statement II are false

Answer

(3) Statement I is false but Statement II is true

Solution

Statement I: In glucose pentaacetate all five –OH groups (including the anomeric –OH) are acetylated, so the molecule cannot open into the free aldehyde form.

As per NCERT, glucose pentaacetate does not react with hydroxylamine; for the same reason it does not react with 2,4-dinitrophenylhydrazine (no free –CHO group).

Statement I is false.

Statement II: As per NCERT, glucose is obtained commercially by the hydrolysis of starch by boiling it with H2SO4 under pressure (2–3 atm):

(C6H10O5)n + nH2O H+ nC6H12O6

Statement II is true.

Answer: (3)