Question

The IUPAC name of the compound \[\left[ Cr{{\left( N{{H}_{3}} \right)}_{5}}NCS \right]\left[ ZnC{{l}_{4}} \right]\]
A.Pentaamine isothiocyanato-N-chromium (III) tetrachloride zincate (II)
B.Pentaamine isothiocyanato-N-chromium (II) tetrachloride zincate (III)
C.Pentaammine thiocyanato-S-chromium (II) tetrachloride zincate (III)
D.Pentaammine thiocyanato-S-chromium (III) tetrachloride zincate (II)

Answer 1

Hint: As per the IUPAC rules, the name of the compound must go in alphabetical order first and then their oxidation numbers have to be written. Here, if the groups of the compound are properly known, then two options get discarded easily.

Complete answer:
The correct answer to this question is option D, Pentaamine thiocyanato-S-chromium (III) tetrachloride zincate (II).
Let us see how this compound has been named. First rule of IUPAC naming says that the elements or groups should be named in alphabetical order for these kinds of compounds. Also, the groups which are stronger are named first and the elements are named after that.
Therefore, as the ammonia group is more powerful here, the first name that we give to the compound is pentaamine, as there are five amines in the given compound.
After that we have another group here called thiocyanate, which is \[NCS\] . The S has been written with it as it shows that oxygen is replaced by sulphur in the cyanate group.
Thereafter, the only remaining element in the bracket is chromium, thus it is written as is. The oxidation state of the first bracket is written, which is three. It is written in roman numerals.
Moving on to the second bracket, there are four chlorine atoms, thus it is called tetrachlorido and with one zinc atom, zincate. Therefore the complete name of the second bracket is tetrachlorido zincate.
As the oxidation state of the second bracket is two, it is written in brackets in roman numerals.
Therefore, the final name of the compound becomes Pentaamine thiocyanato-S-chromium (III) tetrachlorido zincate (II).

So option D is the correct answer

Note:
It is important to know what part of the compound comes first, here as chromium has a positive three oxidation state, the name is followed by cationic complex. The name of the functional groups has to be known as without them the compound cannot be named.