In the reaction

4 NH₃ + 5 O₂ → 4 NO + 6 H₂O

the oxidation number of nitrogen changes from

• –2 to –3

• –2 to +3

• –3 to –2

• –3 to +2

What is the oxidation number of chromium in K₂Cr₂O₇ ?

• +12

• +2

• +3

• +6

In which substance does hydrogen have an oxidation number of zero?

• LiH

• H₂O

• H₂S

• H₂

In which substance is the oxidation number of Cl equal to +1?

• Cl₂

• Cl₂O

• AlCl₃

• HClO₂

What is the oxidation state of phosphorus in the

compound Na₃PO₃?

• 0

• -3

• +3

• +5

In which compound does hydrogen have an oxidation state of –1?

• NaH

• HCl

• H₂O

• NH₃

Oxygen has an oxidation number of –2 in

• O₂

• NO₂

• Na₂O₂

• OF₂

Given the reaction:

Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

The oxidation number of Zn(s) increases because it

• loses electrons

• gains electrons

• loses protons

• gains protons

Tags

NGSS.HS-PS1-2

Which change in oxidation number represents reduction?

• –1 to +1

• –1 to –2

• –1 to +2

• –1 to 0

Tags

NGSS.HS-PS1-7

Given the reaction:

F₂(g) + 2 Br^–(aq) → Br₂() + 2 F^–(aq)

Which species is reduced?

• F₂(g)

• Br^–(aq)

• Br₂ (l)

• F^–(aq)

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2