Question

question 6 of 10
what is the oxidation state of cobalt(iii)?
a. +3
b. +2
c. -3
d. +5

Explanation:

Step1: Understand the Roman numeral notation

The Roman numeral in the name of the element indicates the oxidation state. Here, (III) means 3.

Step2: Determine the sign

In metal - ion naming, positive oxidation states are indicated by Roman numerals. So cobalt(III) has a +3 oxidation state.

Answer:

A. +3