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Flashcards in To study oxidation-reduction reactions Deck (14):
1

Why are halogens suitable to use as oxidising agents?

High electronegativity values i.e have strong attraction for electrons and remove elctrons from other substances which are oxidised

2

What is observed when chlorine gas is bubbled into a solution containing bromide ions and explain?

The colourless solution of bromide ions becomes orange due to the formation of Br2 as Cl2 is oxidising Br- ion to Br2

3

Give the half equation for the oxidation that occurs when chlorine gas is bubbled into a solution containing bromide ions

Cl2 + 2Br- -> 2Cl-+ Br2

4

Why is fluorine not used as an oxidising agent in the school lab?

It is the most electronegative of all halogens and therefore is highly reactive. It is too dangerous to be stored in the school lab

5

What is observed when bromine water is added to a solution containing iodide ions? Explain this observation

Colourless solution of iodide ions turns reddish/brown due to the presence of iodine formed by bromine oxidisng the iodide ions to iodine.

6

Give the half equation for the oxidation that occurs when bromine water is added to a solution containing iodide ions

Br2 + 2I- -> 2Cl- +I2

7

Name the main products formed when chlorine gas is added to a solution of sulfite ions and give the equation

Chloride ions, Sulfate ions, Hydrogen ions
( Cl2 + SO3^2- + H2O -> 2Cl- + SO4^2- + 2 H+

8

When making up a solution of FeSO4, it is important to acidify the solution with dilute sulfuric acid. Why is this necessary

It prevents Fe2+ ions being oxidised to Fe3+ ions by oxygen in the air

9

What ion is formed when chlorine gas is bubbled into a solution of Fe2+ ions? How would you test for the presence of the ion formed?

Fe3+
Add dilute sodium hydroxide solution and a greenish/brown precipitate forms

10

What is observed when a piece of zinc metal is dipped into copper sulfate solution and explain your observation

Immersed zinc becomes coated with a reddish brown substance which is a copper metal formed by zinc reducing Cu2+ ion to Cu metal.

11

Give the half equation for when a piece of zinc metal is dipped into copper sulfate solution

Zn + Cu2+ -> Zn2+ + Cu

12

What is observed when a piece of magnesium metal is dipped into copper sulfate solution and explain

Immersed magnesium becomes coated with a brown substance which is the copper metal which has been formed by the magnesium reducing the Cu2+ to Cu metal.

13

Give the half equation for when a piece of magnesium metal is dipped into copper sulfate solution

Mg + Cu2+ -> Mg2+ + Cu

14

Give one use for the displacement of one metal by another

To protect metals from corrosion and also extracting metals for solutions of their salts