Question

According to Werner's theory, the primary valencies of the central metal atom:

• A. are satisfied by neutral molecules or negative ions.
• B. are equal to its coordination number.
• C. are satisfied by negative ions.
• D. are non-ionisable.

Hint:

Werner theory: Primary valency = oxidation state = ionisable; Secondary valency = coordination number = non-ionisable.

Answer 1

The Correct Option is C

Concept:
According to Werner's theory, a central metal atom or ion has two types of valencies: Primary valency and Secondary valency Primary valency corresponds to oxidation state. Secondary valency corresponds to coordination number.

Step 1: Understand primary valency.
Primary valency is ionisable. It is satisfied by negative ions. For example: \[ [Co(NH_3)_6]Cl_3 \] Here, three chloride ions satisfy the primary valency of cobalt.

Step 2: Understand secondary valency.
Secondary valency is non-ionisable. It is satisfied by ligands, which may be neutral molecules or negative ions. Secondary valency is equal to coordination number.

Step 3: Choose correct statement.
Primary valencies are satisfied by negative ions. Hence: \[ \boxed{\text{(C) are satisfied by negative ions}} \]