An optically pure compound `A,` gave an `[alpha]_(D)^(25)=+30^(@),` while a mixture of `A` and its enantiomer `B`, gave `[alpha]_(D)^(25)=+15^(@),` . The ratio of `A` to `B` in the mixture is

An optically active compound A gave an [alpha]_(0)^(25) = 30^(@) while a mixture of A and its enantiomer B, gave [alpha]_(0)^(25) = +15^(@) . The ratio of A to B in the mixture is

Compound which rotates the plane polarised light is known as optically active compound . On the basis of direction of rotation two forms of an optically active compounds are termed as dextro and laevo rotatory . The two are termed as enantiomers . If we have a 1 : 1 mixture of d and l isomers of a given chiral compound , optical rotation of such mixture is zero Such a mixture is optically inactive and is called a recemic modification. The net specific rotation of any mixture of the d and isomers of a given chiral compound is equal to the weighted average of the rotations due to both the isomers Mathematically if can be expressed as : [alpha]_(net) =f_(d) [alpha_(d)] + f_(1) [alpha_(l)] Where f_(a) and f_(l) are fractions of d and l isomers respectively and [alpha_(d)] , [alpha_(l)] are their specific rotations The pure d isomer of certain chiral compound has [alpha]_(d)^(25) =+ 55^(@) .A non racemic mixture of this compound has a net [alpha]_(d)^(25) =- 11^(@) . What is the fractions of this isomer in mixture ?

A sample of optically active alcohol has a specific rotation, [alpha]_(D)^(25) , equal to +1.151^(@) . Specific rotation for pure form [alpha]_(D)^(25) is +5.756^(@) . What is the percentage enantiomeric excess of the sample?

What can be said with certainity if a compound has [alpha]_(D1)^(25^(@)C)=-9.25^(@)C ?

Equimolar mixture of alpha -D(+)-glucose has specific ([alpha]_(D)) is