Chemistry
Give reasons for the following:
Acid rain has caused damage to heritage structures such as the Taj Mahal.
In the laboratory preparation of oxygen from potassium chlorate – manganese dioxide is added to the reactant.
Oxygen gas does not affect moist blue litmus paper, but carbon dioxide turns it slightly pink.
Oxidation of sulphur results in a product which turns moist blue litmus red.
Combustion and respiration show similarity.
Answer
Acid rain damages heritage buildings because it corrodes metallic surfaces and weakens building materials like statues, marbles, limestone. Taj Mahal is predominantly made of lime stone and it reacts with acids present in acid rain.
In the laboratory preparation of oxygen from potassium chlorate, manganese dioxide acts as a catalyst altering the rate of the reaction. It initiates the decomposition of potassium chlorate (KClO3) at a lower temperature.
As oxygen is neutral in nature so it has no effect on blue litmus paper, but carbon dioxide is slightly acidic in nature, hence it turns blue litmus paper to slightly pink.
The product obtained from the oxidation of sulphur is sulphur dioxide which is a non-metallic acidic oxide. Hence, it turns moist blue litmus red indicating its acidic nature.
Combustion and respiration show similarity because they both involve the breakdown of substances with the use of oxygen to release energy, producing carbon dioxide and water as byproducts.
Related Questions
Match the statements in List I with the correct answer from List II.
List I List II 1. The constituent of air which is around 0.02% A: Nitrogen 2. The constituent of air which is inert or unreactive B: Oxygen 3. The constituent of air which is non-combustible, but supports combustion C: Sulphur dioxide 4. A pollutant in air responsible for acid rain D: Carbon dioxide 5. The main rare gas present in air E: Argon Name the following:
The product formed on oxidation of phosphorus.
The acid formed when the above product of oxidation of phosphorus, reacts with water.
The chemical name of rust.
The pollutant which combines with water vapour to give sulphuric acid – a product of acid rain.
The gas required for both combustion and rusting.
Select the correct answer from the choice in bracket to complete each sentence.
Nitrogen of the air is utilized by plants for formation of …………… [carbohydrates/proteins]
The gas evolved as a product of combustion as well as respiration is ……………[nitrogen dioxide / carbon dioxide].
A candle burns in a jar of oxygen, but gets extinguished in …………… [chlorine/nitrogen]
Air has variable composition and hence there is …………… [less/more] oxygen at lower altitudes than at higher altitudes.
Rusting is a chemical reaction which involves …………… [rapid/slow] oxidation.
Draw a neat labelled diagram to determine the component of air used up in burning, by using phosphorus and a bell jar.