Question

You might have noted that when copper bottom vessel is heated, the surface of copper becomes coated with a black colour substance. When we wash with pithambari powder, the black coating on the surface turns brown.
(i) How has this black coloured substance formed?
(ii) What is that black substance?
(iii) Write the chemical equation of the reaction that takes place.
(iv) Which component of pithambari powder turns black surface of copper to brown and which
can be substituted for pithambari?
(v) Write chemical equation for the change of black colour to brown.

Answer 1

Answer:

question no. 1

This black substance formed on the surface is because of the process called surface oxidation. Upon heating, the copper metal melts gradually and turns black on the surface. This is because the copper powder present in the china dish reacts with the atmospheric oxygen and forms copper (II) oxide.

question no. 2

The black coloured substance is formed due to the reaction of Cu with air.

question no.3

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy It is an exothermic reaction because of a large amount of heat is released. Example: Decomposition of vegetable matter into compost.

question no.4

Contain kewda-Chandan fragrance for the pleasant application. Pitambari has created a milestone by launching its first successful flagship brand ”Pitambari Shining Powder”. It is now effective on 6 metals: Copper, brass, Aluminum, Iron, Silver & Steel utensils.

question no.5

sorry my dear friend I didn't know the answer for your last question