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What is Optical Activity?

by Joy_Chemistry

Optical Activity

In the 19th century, the French physicist Jean Biot discovered an important factor in the stereochemistry of molecules. During one of his research work, Biot investigated the nature of flat polarized light and discovered that solutions of some organic compounds cause the rotation of polarized light. with this property they are called optically active and a polarimeter can be used to determine the amount and direction of rotation. 

 Plane polarized light 

Amount and direction of rotation can be determined with a polarimeter                 

 White light contains electromagnetic waves that oscillate in an infinite number of planes perpendicular to the direction of travel of the light. it’s ordinary white light that has passed through a polarizer. A polarizer is a filter that blocks light waves in all but one plane.A common example is Polaroid sunglasses that prevent glare from polarizing sunlight. 

 enantiomers generally have properties such as physical properties such as boiling point, melting point, refractive index, and density. Chemists working with chiral compounds find it difficult to experiment with enantiomers; However, enantiomers differ in one physical property, namely their ability to rotate plane-polarized light. 

 The light we see is typically unpolarized, that is, it consists of waves evenly distributed in all directions. Planarized light is obtained by passing unpolarized light through a polarizing filter that has light waves that are only oriented in one direction.  

 The optical rotation of a substance differs with the path of the length of the light and its concentration. 

 The proportionality constant [α] is the property of the chiral compound, which is characteristic of a certain compound with fixed wavelength and temperature. The specific rotation of the connection is this constant. The constant is called the specific rotation of the connection. Chemists have compiled a large amount of specific rotation data under standard conditions. 

 The polarimetry technique is used to measure optical activity through a device called a polarimeter.

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