# Optical Activity --- ## Polarimetry An **optically active** compound will rotate plane-polarized light that passes through it, while an **optically inactive** compound will not. --- ## Specific Rotation The **specific rotation** for a compound is the observed rotation of > [!info] Calculating Specific Rotation > > $\text{Specific Rotation}= [\alpha]=\frac{\alpha}{c * l}$ > - $[\alpha]$ = Specific Rotation > - $\alpha$ = Observed Rotation > - $c$ = Concentration in $g/ml$ > - $l$ = Pathlength in decimeters ($1 dm = 10 cm$)