Question

According to Werner's theory of coordination compounds:

• A. primary valency is ionisable
• B. secondary valency is ionisable
• C. primary and secondary valencies are ionisable
• D. neither primary nor secondary valency is ionisable

Answer 1

The correct option is A primary valency is ionisable

Primary valency is ionisable according to Werner's theory of coordination compounds.

According to Werner's coordination theory, there are two kinds of valency, primary and secondary. The primary valency of a central metal ion is satisfied with anions.

For example, in $\left[Cu\right(N{H}_3{)}_4]S{O}_4$ primary valency is 2 and secondary valency is 4.

Secondary valence refers to coordination number. Since copper is coordinated to 4 ammonia ligands, secondary valence is 4. Primary valence is satisfied by anions. Since sulphate ion has $-2$ charge, primary valence is 2.