Question

The reagents with which glucose does not react to give the corresponding tests/products are
A. Tollen's reagent
B. Schiff's reagent
C. HCN
D NH₂OH
E. NaHSO₃
Choose the correct options from the given below:

• A. B and C
• B. A and D
• C. B and E
• D. E and D

Answer 1

The Correct Option is C

- Glucose reacts with Tollen's reagent (A), HCN (C), and $NH_2OH$ (D) to form characteristic products.
- It does not react with Schiff's reagent (B) because it is a mild oxidizing agent, and glucose is a reducing sugar.
- Sodium bisulfite ($NaHSO_3$) (E) does not react with glucose.
Thus, glucose does not react with B and E.

Answer 2

Step 1: Recall the Effect of Electronic Configuration on Reduction Potential 

The reduction potential (\( E^\circ \)) depends on the stability of the resulting electronic configuration.

Step 2: Analyze the Electronic Configurations

• \( Mn^{3+} \) (Manganese 3+): Electronic configuration is \( d^4 \).
• \( Mn^{2+} \) (Manganese 2+): Electronic configuration is \( d^5 \) (a half-filled d-subshell, which is highly stable).

Step 3: Compare with Other Elements

• \( Cr^{3+}/Cr^{2+} \): Does not have a half-filled d-subshell stability.
• \( Fe^{3+}/Fe^{2+} \): Does not have a half-filled d-subshell stability.

Step 4: Conclusion

The \( E^\circ \) value for the \( Mn^{3+}/Mn^{2+} \) couple is more positive because reduction leads to a stable \( d^5 \) configuration.