Oxidation States and Numbers in Chemistry

The video tutorial explains how to find the oxidation number of chromium in chromium(III) hydroxide (Cr(OH)3). It presents two methods: one using the charge of the hydroxide ion and another using an equation setup. Both methods lead to the same result, confirming the oxidation number of chromium as +3. The tutorial emphasizes understanding the neutrality of the compound and the charges of individual ions involved.

What is the overall charge of chromium(III) hydroxide?

• Positive

• Negative

• Neutral

• Depends on the environment

In the first method, what is the charge of the hydroxide ion?

• -2

• +1

• -1

• 0

How many hydroxide ions are present in chromium(III) hydroxide?

• 1

• 4

• 3

• 2

What is the oxidation number of chromium in chromium(III) hydroxide using the first method?

• +1

• +2

• +3

• +4

In the second method, what is the assumed oxidation state of oxygen?

• -1

• -2

• +1

• 0

What is the oxidation state of hydrogen when bonded to oxygen?

• +1

• +2

• -1

• 0

What equation is set up to find the oxidation number of chromium?

• x + 3 = 0

• x - 3 = 0

• x + 3 = 3

• x - 3 = 3

What is the oxidation number of chromium in chromium(III) hydroxide using the second method?

• +3

• +1

• +2

• +4

Do both methods yield the same oxidation number for chromium?

• No

• Yes

• Depends on the method used

• Only in specific cases