Question

Which is NOT correct regarding stock notation?

• A. \(\mathrm{Hg}_{2}(\mathrm{I})\mathrm{Cl}_{2}\) is reduced form of \(\mathrm{Hg}(\mathrm{II})\mathrm{Cl}_{2}\)
• B. \(\mathrm{Hg}(\mathrm{II})\mathrm{Cl}_{2}\) is oxidised form of \(\mathrm{Hg}_{2}(\mathrm{I})\mathrm{Cl}_{2}\)
• C. It helps to identify whether species is present in oxidised form or reduced form
• D. Aurous chloride is written as Au (III) \(\mathrm{Cl}_{3}\)

Hint:

Stock notation shows the oxidation state in roman numerals after the metal name; check the oxidation state of gold in aurous chloride.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
In stock notation the oxidation number of the metal is written in roman numerals in brackets.

Step 2: Check mercury
\(\text{Hg}_2(\text{I})\text{Cl}_2\) has mercury in +1 and \(\text{Hg}(\text{II})\text{Cl}_2\) in +2, so the first two statements are correct.

Step 3: Check the idea
Stock notation tells whether a species is in oxidised or reduced form, so the third statement is correct.

Step 4: Check gold
Aurous means gold(I), so aurous chloride is \(\text{Au}(\text{I})\text{Cl}\), not \(\text{Au}(\text{III})\text{Cl}_3\). The last statement is wrong.

Final Answer:
The statement about aurous chloride is not correct. \[ \boxed{\text{(D) }\text{Aurous chloride is written as Au (III) Cl}_{3}} \]