Stereochemistry

Step 1: Identifying isomers.
The compounds are described as geometrical isomers, and the given options are evaluated based on cis-trans isomerism. Option (1) provides the correct sequence of cis and trans forms.

Step 2: Conclusion.
The correct answer is , , , corresponding to option (1).

Step 1: Stereoisomerism.
Stereoisomerism occurs in compounds that have the same molecular formula but differ in the spatial arrangement of atoms. 2-Butene exhibits cis-trans isomerism, hence it shows stereoisomerism.
Step 2: Conclusion.
The correct answer is (A), 2-Butene.

Step 1: Understanding Meso Compounds.
Meso compounds have chiral centers but are achiral due to internal symmetry. In meso tartaric acid, the two chiral centers have opposite configurations (R and S). The correct configuration for the chiral carbons in meso tartaric acid is 2R, 3S.
Step 2: Conclusion.
The correct answer is (A), 2R, 3S.

Step 1: Identify the possible isomers.
The given compound has double bonds that allow for cis-trans isomerism. Since there are 2 double bonds, there are multiple possible isomers, including cis-trans forms.
Step 2: Conclusion.
Thus, the compound has 4 geometrical isomers.
Final Answer:

Step 1: Understand the concept of optical activity.
Optically active compounds rotate the plane of polarized light. D- (+) tartaric acid is derived from D-glyceraldehyde and shows optical rotation.
Step 2: Conclusion.
Thus, D - (+) tartaric acid is optically active and derived from D - glyceraldehyde.
Final Answer:

Step 1: Identify the stereogenic centers.
Determine the priorities of the substituents attached to each chiral carbon, then use the Cahn-Ingold-Prelog rules to assign the R or S configuration.
Step 2: Conclusion.
Thus, the R and S configuration from top to bottom is R, S, R.
Final Answer:

Step 1: Analyze the compound.
The given compound has two double bonds and can exhibit cis-trans isomerism at both the positions, leading to a total of 4 stereoisomers.
Step 2: Conclusion.
Thus, the compound has 4 stereoisomers.
Final Answer:

Step 1: Optical isomers exist when a compound has chiral centers, meaning that it lacks a plane of symmetry.
Step 2: Among the given options, is chiral and can form optical isomers due to the non-superimposability of its mirror images.

Final Answer: