In a chemical reaction Pentane-2,3,4-triol was synthesized whose one of the optically active form has a specific rotation of +10°. This molecule can exhibit stereoisomerism.

Linked Question 1

If the specific rotation of III is +10°, then what will be the specific rotation of mixture containing 30% of IV, 40% racemization product of rest others.

+ 3°

–3°

–4°

+ 4°

The third

(α₀)_pure = +10° ( $∵$ III & IV are identical)
% of pure = 30% = optical purity $= \frac{{(α_{0})}_{mix}}{{(α_{0})}_{pure}} \times 100 = \frac{{(α_{0})}_{mix}}{10} \times 100$
$∴$ (α₀)_mix = + 3°

Linked Question 2

Select the correct statement:

III and IV are identical.

Total stereoisomer of the molecule is five

Equimolar mixture of II and III will be optically inactive

I and II both are optically active

The third

(A) I & II are meso (optically inactive)
(B) Total stereoisomer is 4
(C) Since II & III are diastereomer, their equimolar mixture will be optically active.

Linked Question 3

The isomers IV and V are

Identicals

Diastereomers

Enantiomers

Meso

The third

III = IV idenitcal
III & V are mirror image & chiral
$∴$ Enantiomers

Sol.(iii)   (A)   I & II are meso (optically inactive)
   (B)    Total stereoisomer is 4
   (C)   Since II & III are diastereomer, their equimolar mixture will be optically active.