Question

Which of the following cation does not form an amine complex with an excess of ammonia?

a.) Al3+

b.) Cd2+

c.) Ag+

d.) Cu2+
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Answer 1

The correct option is d.) Cu2+

Step-by-step explanation:

Only the copper(II) ion (Cu2+) does not form an amine complex when there is an excess of ammonia among the provided cations. This is due to the poor affinity of the copper(II) ion for ammonia and the absence of any unpaired d electrons that could take part in coordination with the ammonia molecules. Therefore, even in the presence of excessive ammonia, the copper(II) ion does not form a stable combination with ammonia and maintains its free state.

Silver(I) ion (Ag+), cadmium(II) ion (Cd2+), and aluminum(III) ion (Al3+) are the other cations that frequently form complexes with ammonia due to their high affinity for it. Three unpaired d electrons on the aluminum(III) ion can align with ammonia molecules to create a stable combination. Two unpaired d electrons in the cadmium(II) ion can align with ammonia molecules to produce a stable combination. One unpaired d electron in the silver(I) ion can align with ammonia molecules to create a stable complex.

Answer 2

`\sf a) Al^(3+)`

Step-by-step explanation:

Amine complexes are formed when a metal cation binds to one or more ammonia molecules. The ability of a metal cation to form an amine complex depends on the number of valence electrons that the cation has.

`\sf \textsf{$\sf Al^(3+ ) $ has only three valence electrons which is to form a stable amine complex. }`

`\sf \textsf{The other cations } Cd^(2+), Ag^+,\textsf{ and } Cu^(2+)` have 10, 11, and 9 valence electrons respectively, which are enough to form stable amine complexes.

Therefore,

`\textsf{The answer is } \sf a.) Al^(3+)`