Chemistry F5 C1 Redox Reaction

When substance X is immersed in dilute nitric acid, a gas is given off. In this reaction, substance X behaves as....

• an alkali

• a salt

• a reducing agent

• an oxidising agent

Which statement defines oxidation?

• gain of electrons

• loss of oxygen

• gaining hydrogen

• increase oxidation number

The following is an oxidation half-equation.

2I- --> I2 + 2e

Based on the equation, which of the following is true?

• Electrons are donated by iodine

• Electrons are accepted by iodine

• Electrons are donated by iodide ions

• Electrons are accepted by iodide ions

What is the oxidation number of manganese in a compound with a formula Mn3(PO4)2?

• 0

• +1

• +2

• +3

When magnesium is immersed in hydrochloric acid, a colourless gas is liberated. What happen to magnesium and hydrogen in the acid?

• Magnesium: is oxidised, Hydrogen: is reduced

• Magnesium: is reduced, Hydrogen: is oxidised

• Magnesium: gains an electron, Hydrogen: loses an electron

What is the change of bromine oxidation number when BrO- ion turns to BrO3- ion?

• +1 --> +5

• -1 --> -5

• +1 --> -5

• +5 --> +1

This figure shows the set-up of the apparatus for an experiment. The bulb lights up when....

• water is added to the glacial ethanoic acid

• the magnesium electrode is replaced with an iron electrode

• methylbenzene is added to the glacial ethanoic acid

• the positions of the magnesium and iron electrodes are interchanged

Figure shows the set-up of the apparatus of a chemical cell. Which of the following statements are true about the cell?

I) the concentration of X2+ ions in the solution decreases.

II) Metal Y donates electrons more easily than metal X.

III) Metal Y acts as the cathode.

IV) Metal X becomes thinner.

• I and II

• I and III

• II and III

• III and IV

Which of the following conducts an electric current but remains chemically unchanged?

• Molten aluminium oxide

• Solid lead (II) bromide

• Ethanol

• Copper

Which of the following conducts electricity entirely by the movement of its ions?

• Potassium metal

• Molten lead (II) bromide

• Graphite

• Mercury