Question

some articles made of silver, copper and iron get coloured coating over them when they are exposed to air .identify the colour and chemical name of the substance of coating in each case.

Answer 1

Silver --◆ black coating.

Silver sulphide.

Copper --◆ green coating.

Copper oxide.

Iron --◆ reddish Brown.

Ferric oxide.

¶ Hope u get it...¶

◆●●◆Thnks◆●●◆

Answer 2

Answer:1. Silver: black coating: Silver sulfide.

2.Copper: green coating: Copper oxide

3. Iron :reddish Brown: Ferric oxide.

Explanation:

Corrosion is the process of slow eating away of metal due to attack of atmospheric gases on the surface of metal resulting into formation of compounds such as oxides, sulfides , carbonates etc is called as corrosion.

1. Corrosion of silver:

$4Ag+2H_2S+O_2\rightarrow 2Ag_2S+2H_2O$

2. Corrosion of copper:

$Cu+O_2\rightarrow CuO$

3. Corrosion of iron is called as rusting. Rust is hydrated ferric oxide $(Fe_2O_3.xH_2O$.

$Fe+O_2\rightarrow Fe_2O_3$