STEREO ISOMERISM

Optical activity is measured by

• Refractometer

• Tracer technique

• Spectrograph

• Polarimeter

The number of optically active isomers of tartaric acid is

• 2

• 3

• 4

• 1

An organic molecule necessarily shows optical activity if it

• Is non-superimposable on its mirror image

• Is superimposable on its mirror image

• Contains asymmetric carbon atoms

• Is non-polaR

How many stereoisomers are there for tartaric acid?

• 3

• 4

• 5

• 0

The number of enantiomers of the compound

CH₃- CH(Br)- CH(Br)COOH is

• 1

• 2

• 3

• 4

A similarity between optical and geometrical isomerism is that

• If in a compound, one is present then so is the other

• Each forms equal number of isomers for a given compound

• Both are included in stereoisomerism

• They have no similarly

(+)–mandelic acid has a specific rotation of +158°. What would be the observed specific rotation of a mixture containing 25 % (–)-mandelic acid and 75 % (+)-mandelic acid?

• + 79°

• –118.5°

• -79°

• +18.5°

Answer explanation

Specific rotation of the mixture = (75/100) (+158°) + (25/100) (–158°) = +79°

Among the following, the most stable compound is

• Cis-1, 2-cyclohexanediol

• Trans-1, 2-cyclohexanediol

• Cis-1, 3-cyclohexenediol

• Trans-1,3-cyclohexanediol

The number of geometrical isomers of CH₃ CH=CH–CH=CH–CH=CH Cl are

• 4

• 6

• 8

• 10

Which of the following is optically active?

• Butane

• 2-methylpentane

• 4-methylpentane

• 3-methylheptane