Oxidation States Quiz-ALL

The oxide of titanium, TiO₂, is used as a ‘whitener’ in toothpaste. It is obtained from the ore iron(II) titanate, FeTiO₃. What is the change, if any, in the oxidation number (oxidation state) of titanium in the reaction FeTiO₃ → TiO₂?

• It is oxidised from +3 to +4.

• It is reduced from +3 to +2.

• It is reduced from +6 to +4.

• There is no change in the oxidation number.

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NGSS.HS-PS1-1

NGSS.HS-PS1-2

In which substance does nitrogen exhibit the highest oxidation state?

• NO

• N₂O

• N₂O₄

• NaNO₂

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NGSS.HS-PS1-2

In which reaction does an element undergo the largest change in oxidation state?

• Cl₂ + 2OH⁻ → OCl⁻ + Cl⁻ + H₂O

• 3Cl₂ + 6OH⁻ → ClO₃⁻ + 5Cl⁻ + 3H₂O

• Cr₂O₇²⁻ + 6Fe²⁺ + 14H⁺ → 2Cr³⁺ + 6Fe³⁺ + 7H₂O

• 3MnO₄²⁻ + 4H⁺ → MnO₂ + 2MnO₄⁻ + 2H₂O

Solutions containing chlorate(I) ions are used as household bleaches and disinfectants. These solutions decompose on heating as shown: 3ClO⁻ → ClO₃⁻ + 2Cl⁻. Which oxidation state is shown by chlorine in each of these three ions?

• +1, +3, -1

• -1, +3, +1

• +1, +5, -1

• -1, +5, +1

Tags

NGSS.HS-PS1-2

In the redox reaction shown, how do the oxidation states of vanadium and sulfur change?

VO₂⁺ + SO₂ → V³⁺ + SO₄²⁻

• Vanadium: +1 to +3, Sulfur: 0 to -2

• Vanadium: +1 to +3, Sulfur: +4 to +6

• Vanadium: +5 to +3, Sulfur: 0 to -2

• Vanadium: +5 to +3, Sulfur: +4 to +6

Tags

NGSS.HS-PS1-2

The following half reactions occur when potassium iodate(V), KIO₃, in hydrochloric acid solution oxidises iodine to ICl₂⁻. IO₃⁻ + 2Cl⁻ + 6H⁺ + 4e⁻ → ICl₂⁻ + 3H₂O I₂ + 4Cl⁻ → 2ICl₂ + 2e⁻ What is the ratio of IO₃⁻ to I₂ in the balanced chemical equation for the overall reaction?

• 1:1

• 1:2

• 1:4

• 2:1

A 10 cm³ sample of 0.30 mol dm⁻³ Tl⁺NO₃⁻ required 20 cm³ of 0.10 mol dm⁻³ acidified NH₄VO₃ to oxidise it to Tl³⁺ in solution. Vanadium is the only element reduced in this reaction. What is the oxidation number of the vanadium in the reduced form?

• +1

• +2

• +3

• +4

Tags

NGSS.HS-PS1-2

In which reaction does hydrogen behave as an oxidising agent?

• H₂ + Cl₂ → 2HCl

• C₂H₄ + H₂ → C₂H₆

• N₂ + 3H₂ → 2NH₃

• 2Na + H₂ → 2NaH

Tags

NGSS.HS-PS1-2

Arsenic chloride, AsCl₃, reacts with sodium borohydride, NaBH₄. pAsCl₃ + qNaBH₄ → rAsH₃ + sNaCl + tBCl₃. What are the numbers p, q, r, s, and t when this equation is balanced correctly?

• 2, 3, 2, 3, 1

• 3, 2, 3, 3, 2

• 4, 3, 4, 3, 3

• 4, 4, 4, 3, 3

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

Sodium chromate(VI), Na₂CrO₄, is manufactured by heating chromite, FeCr₂O₄, with sodium carbonate in an oxidising atmosphere. Chromite contains Cr₂O₄²⁻ ions. 2FeCr₂O₄ + 4Na₂CO₃ + 7/2O₂ → 4Na₂CrO₄ + Fe₂O₃ + 4CO₂. What happens in this reaction?

• Chromium and iron are the only elements oxidised.

• Chromium, iron and carbon are oxidised.

• Only chromium is oxidised.

• Only iron is oxidised.