Question

No. Of stereoisomers of ch3-ch=ch-ch(oh)-ch3

Answer 1

Answer : The number of stereoisomers of $CH_3CH=CH-CH(OH)-CH_3$ are, 4

Explanation :

Stereoisomers : It is defined as the isomers which are having same molecular formula, same bonding arrangement but different arrangement of atoms in space.  

Pair of molecules (optical isomers) that are mirror images of each other are said to be enantiomers whereas pairs that are not mirror images of each other are said to be diastereomers.

The rules for cis-trans system are :

The atoms or groups attached to each olefinic carbon are given priority as per the sequence rule.

If the higher priority groups are present on same sides across the double bond, the geometrical isomer is said to have 'cis'.

If the higher priority groups are present on opposite sides across the double bond, the geometrical isomer is said to have 'trans'.

In the given compound, higher priority groups are $CH(OH)-CH_3$ and $CH_3$.

When $CH(OH)-CH_3$ and $CH_3$ are present on same sides across the double bond, the geometrical isomer is said to have 'cis'.

When $CH(OH)-CH_3$ and $CH_3$ are present on opposite sides across the double bond, the geometrical isomer is said to have 'trans'.

Hence, the number of stereoisomers of $CH_3CH=CH-CH(OH)-CH_3$ are, 4

Answer 2

Answer:

four

Explanation:

number of steriocenters=2(double bond and chiral carbon). Absence of plane of symmetry , so no meso forms. Total stereoisomers=2^n=2^2= 4 isomers