givereason:
1.lemon is used for restoring the shine of tarnished copper vessels.
2.a metal sulphide is converted into its oxide to extract metal from it.
 

Asked by manya.bhardwaj.01 | 28th Oct, 2017, 11:01: AM

Expert Answer:

1. Lemon contains citric acid. Tamarind contains tartaric acid. This acid neutralises the copper carbonate and dissolves the layer. The copper carbonate is formed as a result of its exposure t the moist carbon dioxide present in the air.
 
2. It is because the metals can be extracted easily when converted into its oxide.

Answered by  | 28th Oct, 2017, 10:49: PM