Displacement Reactions and Color Changes

The video tutorial explains displacement reactions, where atoms of one element replace those of another in a compound. An example is given with an iron knife in copper sulphate solution, where iron displaces copper due to higher reactivity. An experiment is set up with beakers containing different sulphate solutions and metals to observe displacement reactions. Observations show color changes in solutions where reactions occur, confirming the concept of more reactive metals displacing less reactive ones.

What is a displacement reaction?

• A reaction where atoms of one element are replaced by atoms of another element.

• A reaction where energy is absorbed from the surroundings.

• A reaction where two elements combine to form a compound.

• A reaction where a compound breaks down into simpler substances.

In the example with the iron knife and copper sulfate, what forms on the iron knife?

• A white powder

• A green precipitate

• A blue solution

• A reddish-brown precipitate

Why does iron displace copper from the copper sulfate solution?

• Because iron is less reactive than copper

• Because copper is less reactive than iron

• Because iron is more reactive than copper

• Because copper is more reactive than iron

What is added to beaker 1 in the activity?

• Copper sulfate

• Zinc granules

• Copper turnings

• Iron nails

Which beakers show a change in color during the activity?

• Beakers 2 and 3

• Beakers 1 and 2

• Beakers 3 and 4

• Beakers 4 and 5

What happens to the color of the copper sulfate solution in beaker 1?

• It changes from blue to green

• It changes from blue to colorless

• It remains blue

• It changes from blue to red

What substance gets deposited at the bottom of beaker 1?

• Copper

• Sulfur

• Zinc

• Iron

In beaker 2, what color does the solution change to?

• Yellow

• Red

• Green

• Blue

What is the conclusion about displacement reactions?

• They occur between less reactive metals and more reactive metals.

• They occur between more reactive metals and less reactive metals.

• They do not involve any change in reactivity.

• They only occur in non-metallic elements.

Which of the following is true about displacement reactions?

• They always produce a gas.

• They involve the replacement of atoms in a compound.

• They do not change the color of the solution.

• They only occur in solid-state reactions.