Polarized light rotation

Addition of hydroxide occurs as a rapid follow-up reaction. Even if the alkyl halide was chiral before the carbocation formed, racemization occurs about the central carbon atom because the hydroxide can bond to the planar central carbon from either side (see Figure 8.17(b)). Statistically, equal numbers of each racemate are formed, so the angle through which the plane polarized light rotated during reaction will, therefore, decrease toward 0°, when reaction is complete. 

The rotation of polarized light.—Rotation of polarized light7 is additive for soln. of mixtures of salts which do not form double salts, and there is a marked deviation from the additive law for mixtures known to form double salts. 

Circular dichroism is closely related to optical rotatory dispersion, the variation of optical rotation with wavelength. Optical rotation depends upon the difference in refractive index (t)l tIr) between left-handed and right-handed polarized light. Rotation a... 

Plane-polarized light Rotated plane-polarized light... 

In cross-polarized light, rotate the stage 45 from crystal extinction (darkness) as illustrated in Photograph 6-2. For crystals that exhibit a strongly wavy (undulatory) extinction, birefringence data may be questionable. Therefore, crystals with uniform or nearly uniform extinction are sought. 

Why is Plane Polarized Light Rotated by a Chiral Medium ... 

A FIGURE 20.4 Rotation of Plane-Polarized Light Plane-polarized light rotates as it passes through a sample containing only one of two optical isomers. 

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