Question

A co-ordination complex has the formula $PtC{l}_4.2KCl$. Electrical conductance measurements indicate the presence of three ion in one formula unit. Treatment with $AgN{O}_3$ produces no precipitate of $AgCl$. What is the co-ordination number of Pt in this complex?

• A. $4$
• B. $6$
• C. $5$
• D. $3$

Answer 1

The correct option is B $6$

$PtC{l}_4.2KCl\equiv K_2\left[PtC{l}_6\right]{\rightleftharpoons }^{aq}2K^{+}+[PtC{l}_6{]}^{2+}$
So, it has three ions per formula unit. The $C{l}^{–}$ is present in coordination sphere so it will not give white precipitate with silver nitrate solution. So in the compound the coordination number of platinum is 6.