Olympiad Electrochem

An oxidizing agent will

• increase in mass

• lose electrons

• be reduced

• increase in oxidation number

Tags

NGSS.HS-PS1-2

In a redox reaction, the species that loses electrons

• is called the cathode

• is oxidized

• gains mass at the electrode

• decreases in oxidation number

As an element is oxidized, its oxidation number

• decreases as electrons are lost

• increases as electrons are lost

• decreases as electrons are gained

• increases as electrons are gained

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Oxidation-reduction reactions occur because of the competition between particles for

• electrons

• positrons

• protons

• neutrons

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Mg + PbCl₂ → MgCl₂ + Pb

Which statement correctly describes the oxidation and reduction that occur?

• Mg is oxidized and Pb²⁺ is reduced

• Mg is oxidized and Cl^- is reduced

• Mg is reduced and Cl^- is oxidized

• Mg is reduced and Pb²⁺ is oxidized

Tags

NGSS.HS-PS1-2

In the reactions

Sn²⁺(aq) + 2Fe³⁺(aq) -> Sn⁴⁺(aq) + 2Fe²⁺(aq),

the reducing agent is

• Fe³⁺

• Sn²⁺

• Sn⁴⁺

• Fe²⁺

Tags

NGSS.HS-PS1-2

Pb(s) + 2Ag⁺(aq)→ Pb²⁺(aq) + 2Ag(s)

The chemical species being reduced is

• Ag

• Pb

• Pb²⁺

• Ag⁺

If acidified potassium dichromate(VI) (K₂Cr₂O₇) acts as oxidizing agent, color changes from

• orange to red

• orange to green

• yellow to green

• yellow to red

Tags

NGSS.HS-PS1-2

In electrolysis of copper purification, at cathode

• pure copper gets deposited

• the object to be electroplated is kept

• impure copper gets deposited

• CuSO₄ gets deposited

An electrolytic cell uses electrical energy to drive

• chemical reaction

• physical reaction

• no reaction

• none of above

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-4