Chemical Reactions — Set 3
Chemistry · रासायनिक अभिक्रियाएं · Questions 21–30 of 40
Which metal is used for galvanizing iron to protect it from rusting?
Correct Answer: D. Zinc
• **Zinc** = Zinc provides a protective coating that prevents oxygen and moisture from reaching the iron. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Copper; B: Aluminum; C: Tin
What is the main component of 'Natural Gas' involved in combustion?
Correct Answer: C. Methane
• **Methane** = Methane is the simplest hydrocarbon and the primary constituent of natural gas. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Ethane; B: Butane; D: Propane
The digestion of food in our body is an example of which type of reaction?
Correct Answer: C. Decomposition reaction
• **Decomposition reaction** = Digestion involves breaking down complex food molecules into simpler substances like glucose. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Displacement reaction; B: Addition reaction; D: Combination reaction
Silver articles turn black after some time when exposed to air due to the formation of?
Correct Answer: B. Silver sulfide
• **Silver sulfide** = Silver reacts with hydrogen sulfide present in the air to form a black coating. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Silver nitrate; C: Silver chloride; D: Silver oxide
Which of the following reactions is used in black and white photography?
Correct Answer: B. Decomposition of silver chloride
• **Decomposition of silver chloride** = Silver chloride decomposes into silver and chlorine when exposed to sunlight. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Neutralization of acids; C: Oxidation of copper; D: Combination of iron and sulfur
What is produced when Magnesium ribbon is burnt in air?
Correct Answer: B. Magnesium oxide
• **Magnesium oxide** = Magnesium reacts with atmospheric oxygen to form a white powder of magnesium oxide. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Magnesium nitride; C: Magnesium carbonate; D: Magnesium hydroxide
A reaction in which heat is absorbed from the surroundings is called?
Correct Answer: A. Endothermic
• **Endothermic** = Endothermic reactions require energy to proceed, resulting in a cooling effect on the surroundings. • (Contextual detail from explanation) • 💡 Wrong-option analysis: B: Exothermic; C: Reversible; D: Irreversible
The reaction between Barium Chloride and Sodium Sulfate to form Barium Sulfate is a?
Correct Answer: A. Double displacement
• **Double displacement** = In this reaction, the two compounds exchange ions to form two new compounds. • (Contextual detail from explanation) • 💡 Wrong-option analysis: B: Single displacement; C: Combination; D: Decomposition
What does the symbol (aq) written after a chemical formula represent?
Correct Answer: C. Aqueous solution
• **Aqueous solution** = The correct answer is 'Aqueous solution'. • (Contextual detail from explanation) • 💡 Wrong-option analysis: A: Anhydrous solid; B: Acidic solution; D: Air-tight state
Which law states that mass is neither created nor destroyed in a chemical reaction?
Correct Answer: B. Law of Conservation of Mass
• **Law of Conservation of Mass** = The Law of Conservation of Mass requires that the total mass of reactants equals the total mass of products. • **Mass** — The Law of Conservation of Mass requires that the total mass of reactants equ... • 💡 Wrong-option analysis: A: Law of Definite Proportions; C: Law of Multiple Proportions; D: Avogadro's Law