Geometrical isomerism in Acetophenone-oxime:

Geometrical isomerism is the phenomenon in which compounds have the same molecular formula but differ in the spatial arrangement of their atoms. It occurs when there is restricted rotation around a bond due to the presence of a double bond or a ring structure.

Detailed Explanation:

In the case of Acetophenone-oxime, the oxime group (-NOH) is attached to the carbonyl group (C=O) of the acetophenone molecule. The oxime group consists of a nitrogen atom bonded to a hydrogen atom and an oxygen atom.

The oxime group can exist in two different forms due to the presence of a double bond between the nitrogen and oxygen atoms. These two forms are referred to as the E-isomer and the Z-isomer.

Explanation of E-isomer:

In the E-isomer, the nitrogen atom and the oxygen atom are on opposite sides of the double bond. This arrangement is referred to as trans configuration. The E-isomer is more stable due to the presence of a larger dipole moment, as the electronegative oxygen atom is placed far from the electronegative nitrogen atom.

Explanation of Z-isomer:

In the Z-isomer, the nitrogen atom and the oxygen atom are on the same side of the double bond. This arrangement is referred to as cis configuration. The Z-isomer is less stable due to the presence of a smaller dipole moment, as the electronegative oxygen atom is placed closer to the electronegative nitrogen atom.

Conclusion:

In Acetophenone-oxime, geometrical isomerism is possible because the oxime group can exist in two different forms, E-isomer and Z-isomer, based on the spatial arrangement of atoms around the double bond between the nitrogen and oxygen atoms. Therefore, the correct answer is (c) Acetophenone-oxime.

Acetophenone - oxime ( R-C=N-OH and R' is also attach with C )