9.1 Oxidation number

Which statement is correct?

• Oxidation is loss of elec and a decrease in oxidation state.
• Oxidation is gain of elec and an increase in oxidation state
• Reduction is loss of elec and increase in oxidation state.
• Reduction is gain of elec and a decrease in oxidation state.

What are the oxidation numbers of elements in sulfuric acid, H₂SO₄?

• A
• B
• C
• D

What are the oxidation numbers of elements in phosphoric acid, H₃PO₄?

• A
• B
• C
• D

Which are examples of reduction?

• I and II
• I and III
• II and III
• I, II and III

Tags

NGSS.HS-PS1-2

Which change does nitrogen undergo oxidation?

• A
• B
• C
• D

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which statement is correct?

• H₂SO₃ is reducing agent because it undergoes reduction.
• H₂SO₃ is reducing agent because it undergoes oxidation.
• Sn⁴⁺ is oxidizing agent because it undergoes oxidation
• Sn⁴⁺ is reducing agent because it undergoes oxidation

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What happens to vanadium during reaction VO²⁺ → VO₃^-

• Undergo oxidation and oxidation number changes from +4 to +5
• Undergo oxidation and oxidation number changes from +2 to +4
• Undergo reduction and oxidation number changes from +2 to -1
• Undergo reduction and oxidation number changes from +4 to +2

What is the reducing agent in this reaction?

• Cu
• NO₃^-
• Cu²⁺
• H⁺

Tags

NGSS.HS-PS1-2

Oxidation number of chromium is the same in all compounds except

• Cr(OH)₃
• Cr₂O₃
• Cr₂(SO₄)₃
• CrO₃

What happens to Cr³⁺ ion when it is converted to CrO₄^2–

• Oxidation number decreases and it undergo reduction
• Oxidation number decreases and it undergo oxidation
• Oxidation number increases and it undergo reduction
• Oxidation number increases and it undergo oxidation

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2