Which one of the following is not a redox reaction?

• Br₂ +SO₂ +2H₂O → SO₄^2– +4H+ +2Br^–

• SnCl₂ + HgCl₂ → Hg + SnCl₄

• Cu₂O+H₂SO₄ → CuSO₄ +Cu+H₂O

• 2CrO₄^2– + 2H⁺ → Cr₂O₇^2– + H₂O

Tags

NGSS.HS-PS1-2

Molecules or ions that contain an element with an oxidation state of +5 include

1 H₂SO₃

2 NO₂⁺

3 [Cr(H₂O)₄Cl₂]⁺

4 ClO₃^-

• 1, 2 and 3 only correct

• 1 and 3 only correct

  NO₂⁺

• 2 and 4 only correct

• 4 only correct

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What happens to the Cr³⁺ (aq) ion when it is converted to CrO₄²⁻ (aq)?

• Its oxidation number decreases and it undergoes reduction.

• Its oxidation number decreases and it undergoes oxidation.

• Its oxidation number increases and it undergoes reduction.

• Its oxidation number increases and it undergoes oxidation.

Tags

NGSS.HS-PS1-2

The following reactions are spontaneous as written.

Fe(s) + Cd²⁺ (aq) → Fe²⁺ (aq) + Cd(s)

Cd(s) + Sn²⁺ (aq) → Cd²⁺ (aq) + Sn(s)

Sn(s) + Pb²⁺ (aq) → Sn²⁺ (aq) + Pb(s)

Which of the following pairs will react spontaneously?

I. Sn(s) + Fe²⁺ (aq)

II. Cd(s) + Pb²⁺ (aq)

III. Fe(s) + Pb²⁺ (aq)

• I only

• II only

• III only

• II and III only

Tags

NGSS.HS-PS1-2

What is the oxidation number of chlorine in HClO?

• 0

• -1

• +1

• +5

Oxidation is the _________ of electrons.

• loss

• gain

• sharing

• transfer

Tags

NGSS.HS-PS1-7

Reduction is the ___________ of electrons.

• loss

• gain

• sharing

• transfer

What is the oxidation number of nitrogen in N₂?

• -3

• 0

• +4

• -1

What is the oxidation number of iodine in KIO₃?

• 0

• -1

• +5

• +1

What substance is oxidized in the following reaction?
4Fe + 3O₂ --> 2Fe₂O₃

• Iron
• Fluorine
• Oxygen