Question

Which will form geometrical isomers ?

• A.
• B. $C{H}_{3}CH=NOH$
• C.
• D. All of these

Answer 1

The correct option is D All of these

Geometrical isomerism is shown by any species which can have more than one different ways to orient its attached groups in $3D$ space.
It can be with respect to a cyclic ring or across a double bond(in both these cases, there is restricted rotation which leads to different arrangements). To show geometrical isomerism across a double bond, the two groups bonded to each geometrical centre (here it is the atom involved in double bond) must be different. Similarly, about a ring, the groups are different at geometrical centres to show any geometrical isomers.
In option (a), two $Cl$ may be either at same side or at opposite side. In option (b), there are different orientation of $OH$ and lone pair on $N$ atom about the double bond. In option (c), the two $H$ on the two carbons involved in double bond are either at same side or opposite side.
Hence, (d) is correct.