Why Cu is a poor reducing agent-explain.

Why Cu is a poor reducing agent-explain? 

Explanation: 

Copper has a positive standard reduction potential.This means that copper does not react with aqueous  H⁺ ions to release H_{2 .}

The reaction simply does not occur. The tendency of copper to change into Cu(II)  ion  is extremely small.

 Hence, copper is a particularly poor reducing agent .

The standard reduction potential of copper ( E) at 25 ⁰C is given below,

What is the spin only magnetic moment of [ Cu ( NH₃ ) ] ₄ ²⁺ ion ?

In this complex ion , [ Cu ( NH3 ) ]₄ ²⁺,the oxidation state of copper is +2 . Because , ammonia is a neutral ligand .

Now ,the atomic number of Cu atom is 29 . So, the number of electron of Cu ⁺² ion is 27. So, Cu ⁺² ion is a 3d ⁹ system .Now, ammonia ( NH₃ ) is a strong field ligand.

According to crystal field theory the complex will be a low spin complex and its electronic distribution will be e_g⁴ t_2g⁵ which is shown below.

From the above electronic arrangement , it has been found that Cu ⁺² ion has one unpaired only.

So the calculated spin only magnetic moment is 1.73 B.M . The calculation of spin only magnetic moment of [ Cu ( NH₃ ) ] ₄ ²⁺ ion is shown below.

What is the spin only magnetic moment of Cu ⁺ ion ?

Now ,the atomic number of Cu atom is 29 . So, the number of electron of Cu ⁺ ion is 28. So, Cu ⁺ ion is a 3d ¹⁰ system . 

Since Cu ⁺ ion contains full filled d-orbital , hence it has no unpaired .The spin only magnetic moment of Cu ⁺ ion is zero . 

Summary:

What is the spin only magnetic moment of [ Cu ( NH₃ ) ] ₄ ²⁺ ion ?

What is the spin only magnetic moment of Cu ⁺ ion ? 

Why copper is a poor reducing agent ? 

Lanthanide contraction and its consequences