Q. 524.2( 20 Votes )
When a copper object is exposed to moist air for a long t e, then a green coating is formed on its surface.
(a) What is the material of the green coating?
(b) State whether the green coating is acidic or basic.
(a) When copper vessel is exposed to moist air for a long time it develops a green layer on its surface. Copper corrodes by oxidation in which it reacts with oxygen in the air to form copper oxide. Copper oxide then combines with carbon dioxide to make copper carbonate, which gives it a green colour. This process is called corrosion of copper. The green material is a mixture of copper hydroxide (Cu(OH)2) and copper carbonate (CuCO3). The following is the reaction
2Cu+H2O+CO2+O2→Cu (OH)2 + CuCO3
(b) The green coating will be basic in nature. Green coating is made of copper oxide which is an oxide of metal. Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases.
Rate this question :
Distinguish between metals and non-metals on the basis of their chemical properties.All in One - Science
The least reactive metal among the following is:Lakhmir Singh & Manjit Kaur - Science
The element Z burns in air to form an oxide. The aqueous solution of this oxide turns blue litmus to red. The element Z is most likely to be:Lakhmir Singh & Manjit Kaur - Science
Which of the following reactions will not occur? Why not?
(a) Zinc sulphate + Copper Copper Sulphate + zinc
(b) Copper Sulphate + Iron iron Sulphate + copperLakhmir Singh & Manjit Kaur - Science
Which among the following is the most reactive metal?Lakhmir Singh & Manjit Kaur - Science
When a vessel is exposed to moist air for a long time, then a green coating is formed on its surface. The vessel must be made of:Lakhmir Singh & Manjit Kaur - Science
You are given a solution of iron sulphate. Which of the following do you think cannot displace iron from iron sulphate?Lakhmir Singh & Manjit Kaur - Science
Which of the following elements will produce an oxide that will dissolve in water to form an acid?Lakhmir Singh & Manjit Kaur - Science
An element burns in air to form an oxide. The aqueous solution of this oxide turns blue litmus paper red. State whether the element is a metal or nonmetal. Name one such element.Lakhmir Singh & Manjit Kaur - Science
The metal X reacts with dilute hydrochloric acid to form a gas Y. The metal X also reacts with sodium hydroxide solution (on heating) to form the same gas Y. When a lighted matchstick is applied, this gas burns by producing a ‘pop’ sound.
(a) name two metals which could behave like X
(b) Name the gas YLakhmir Singh & Manjit Kaur - Science