Question

The number of geometrical isomers for \[\left[ Pt{{\left( N{{H}_{3}} \right)}_{2}}C{{l}_{2}} \right]\]
A Two
B One
C Three
D Four

Answer 1

Hint: The geometrical isomers are stereoisomers (space isomerism) in which compounds have the same molecular formula but differ in the arrangement of atoms in space (inside the coordinate sphere). Geometrical isomers are trans (same atoms on the same side) and cis isomers (same atom on a different side). In alkenes (hydrocarbons) geometrical isomerism is possible in which atom around the carbons is arranged in space differently.

Complete answer:In the given question, the coordinate complex contains a central metal atom that is surrounded by secondary valency (which can be determined by the coordination number), two are ammonia ligands and the other two are chloride ligands. Now the arrangement of all four ligands around the central metal is like a square-like structure.
Now when both ammonia ligands and also both chloride are present on the same side then the isomer is said to be a cis isomer as compared to the trans isomer compound in which both chloride ligands are present at opposite corners and also ammonia ligands. Now both are said to be geometrical isomers of each other, so the given compound has two geometrical isomers (cis and trans).

Thus, the correct option is A

Note: The cis and trans isomers are the compounds in which ligands arrangement in space is different but there is no movement and no exchange of ligands and metal ions from one sphere to another (the molecular formula is the same but the arrangement of ligands around the central metal atom is different). The compounds whose molecular formula is the same are said to be isomers of each other and the phenomenon is known as isomerism.