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

The isomers IV and V are

Enantiomers

Identicals

Meso

Diastereomers

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.

Linked Question 2

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.

–4°

–3°

+ 4°

+ 3°

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 3

Select the correct statement:

I and II both are optically active

Equimolar mixture of II and III will be optically inactive

III and IV are identical.

Total stereoisomer of the molecule is five

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.