Difficult
$A$ student has been collecting silver coins and copper coins. One day she observed a black coating on silver coins and a green coating on copper coins. Which chemical phenomenon is responsible for these coatings? Write the chemical name of black and green coatings.
(N/A) The chemical phenomenon responsible for these coatings is $Corrosion$.
Silver coins develop a black coating of $Silver \text{ } Sulphide$ $(Ag_2S)$ due to the reaction with sulphur compounds present in the air.
Copper coins develop a green coating of $Basic \text{ } Copper \text{ } Carbonate$ $(CuCO_3 \cdot Cu(OH)_2)$ due to the reaction with moist carbon dioxide and oxygen in the air.
Silver coins develop a black coating of $Silver \text{ } Sulphide$ $(Ag_2S)$ due to the reaction with sulphur compounds present in the air.
Copper coins develop a green coating of $Basic \text{ } Copper \text{ } Carbonate$ $(CuCO_3 \cdot Cu(OH)_2)$ due to the reaction with moist carbon dioxide and oxygen in the air.
Explore More
Similar Questions
Write balanced chemical equations for the following reactions:
$(i)$ Calcium carbonate on reaction with hydrochloric acid gives calcium chloride,water and carbon dioxide.
$(ii)$ Nitrogen reacts with hydrogen under pressure to form ammonia.
$(iii)$ Carbon disulphide burns in air to give carbon dioxide and sulphur dioxide.
$(i)$ Calcium carbonate on reaction with hydrochloric acid gives calcium chloride,water and carbon dioxide.
$(ii)$ Nitrogen reacts with hydrogen under pressure to form ammonia.
$(iii)$ Carbon disulphide burns in air to give carbon dioxide and sulphur dioxide.
Medium
View SolutionWrite the balanced chemical equations for the following reactions and identify the type of reaction in each case.
$(a)$ Ethanol is warmed with ethanoic acid to form ethyl acetate in the presence of concentrated $H_2SO_4$.
$(b)$ Ethene is burnt in the presence of oxygen to form carbon dioxide, water and releases heat and light.
$(a)$ Ethanol is warmed with ethanoic acid to form ethyl acetate in the presence of concentrated $H_2SO_4$.
$(b)$ Ethene is burnt in the presence of oxygen to form carbon dioxide, water and releases heat and light.
Medium
View SolutionFerrous sulphate decomposes with the evolution of a gas having a characteristic odour of burning sulphur. Write the chemical reaction involved and identify the type of reaction.
Medium
View SolutionWhy is a combustion reaction considered an oxidation reaction?
Easy
View SolutionWhich among the following changes are exothermic or endothermic in nature?
$(a)$ Decomposition of ferrous sulphate
$(b)$ Dilution of sulphuric acid
$(c)$ Dissolution of sodium hydroxide in water
$(d)$ Dissolution of ammonium chloride in water
$(a)$ Decomposition of ferrous sulphate
$(b)$ Dilution of sulphuric acid
$(c)$ Dissolution of sodium hydroxide in water
$(d)$ Dissolution of ammonium chloride in water
Medium
View SolutionVedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo