Question

1. All of the following compounds are formed by nickel in +2 oxidation state. Which one has the incorrect molecular formula?

(A) K4[Ni(CN)6] (B) K3[Ni(CN)4] (C) [Ni(en)3](BF4)2 (D) [Ni(NH3)6]Br2

please explain!!!

Answer 1

(B) K3[Ni(CN)4]

    The oxidation number of K = +1

   The oxidation number of CN^- = -1

+1*3 + x+ (--1*4) = 0

3 +x-4 = 0

   x -1 = 0

x = +1

The oxidation number of Ni is +1 in K3[Ni(CN)4]. So it is incorrect

(B) K3[Ni(CN)4] >>>>>answer

A. K4[Ni(CN)6]

     +1*4 +x+ (-1*6) = 0

           x = +2

    The oxidation number of Ni is +2

[Ni(en)3](BF4)2 -----------> [Ni(en)3]^2+ +2(BF4)^-

[Ni(en)3]^2+

x + (0*3 ) = +2

x = +2

The oxidation number is +2

(D) [Ni(NH3)6]Br2 --------------> [Ni(NH3)6]^2+ + 2Br^-

   [Ni(NH3)6]^2+

   x + (0*6) = +2

   x = +2

The oxidation number of Ni is +2

  

    

  

(B) K3[Ni(CN)4]