Redox reactions

Question 1

What are the 3 most electronegative elements?

Answer 1

1. Fluorine
2. Oxygen
3. Nitrogen

Question 2

Which atom in a compound is electronegative and which is electropositive?

Answer 2

Non-metals tend to be more electronegative while metals tend to be more electropositive.

Question 3

In a compound which atom has the negative/positive oxidation number?

Answer 3

More electronegative atom -negative
Less electronegative atom
-positive

Question 4

How to tell which element is more electronegative?

Answer 4

Electronegativity increases from left to right across a period and decreases down the group. (more electronegative, more strongly the atom is able to attract bonding electrons towards itself)

Question 5

Define oxidation in terms of electron transfer.

Answer 5

Oxidation is the loss of electrons from an element, compound or ion.

Question 6

Define oxidation in terms of oxidation state.

Answer 6

Oxidation is the increase in oxidation state of an element, compound or ion.

Question 7

Define reduction in terms of transfer of electrons.

Answer 7

Reduction is the gain of electrons from an element, compound or ion.

Question 8

Define reduction in terms of oxidation state.

Answer 8

Reduction is the decrease in oxidation state of an element, compound or ion.

Question 9

What equations are not redox equations?

Answer 9

• Neutralisation
• Precipitation
• Thermal decomposition of carbonates
• Acid + carbonate

Question 10

How does H2O2 function as an agent (oxidising/reducing)?

Answer 10

With a strong oxidising agent (MnO4^-), H2O2 is a reducing agent.
With a strong reducing agent (I^-), H2O2 is an oxidising agent.

Question 11

Reaction of iodine with sodium thiosulfate.

Answer 11

I2 + 2S2O3^2- –> 2I^- + S4O6^2-

Question 12

Reaction of iodine ion solution with potassium iodide.

Answer 12

2MnO4^- + 16H^+ + 10I^- –> 2Mn^2+ + 8H2O + 5I2