Advices For Studying Organic Chemistry

3. A substance that rotates plane-polarized light in the clockwise direction is said to
   be dextrorotatory, and one that rotates plane-polarized light in a
   counterclockwise direction is said to be levorotatory (Latin: dexter, right; and
   laevus, left).

5.7C SPECIFIC ROTATION: [α]DT

1. Specific rotation, [α]:

[]α TD = (^) lαx c^
α: observed rotation^
l: sample path length (dm)
c: sample concentration (g/mL)
Path length, l (dm) x Concentration of sample, c (g/mL) l x c
[α]DT = Observed^ rotation,^ α = α^

1. The specific rotation depends on the temperature and wavelength of light that
   is employed.
   i) Na D-line: 589.6 nm = 5896 Å.
   ii) Temperature (T).


2. The magnitude of rotation is dependent on the solvent when solutions are
   measured.

2. The direction of rotation of plane-polarized light is often incorporated into the
   names of optically active compounds:

C

CH 3

H

CH 2

CH (^3)
H C
CH 3
HO OH
CH 2
CH (^3)