Chemical Reactions — Set 2
Chemistry · रासायनिक अभिक्रियाएं · Questions 11–20 of 40
Which catalyst is traditionally used in the hydrogenation of vegetable oils?
Correct Answer: D. Nickel
Nickel serves as a catalyst to speed up the addition of hydrogen to unsaturated fats. This process converts liquid vegetable oils into solid fats like vanaspati ghee. A catalyst remains chemically unchanged at the end of the reaction.
A substance that increases the rate of a chemical reaction without being consumed is a?
Correct Answer: B. Catalyst
A catalyst lowers the activation energy required for a reaction to proceed. It provides an alternative pathway for the reaction to occur more quickly. Enzymes are biological catalysts found in living organisms.
What is the insoluble solid formed during a chemical reaction called?
Correct Answer: C. Precipitate
A precipitate is an insoluble solid that emerges from a liquid solution during a reaction. This often occurs in double displacement reactions involving ionic compounds. It can be separated from the mixture through the process of filtration.
Which gas is used in the storage of fat-containing food items for a long time?
Correct Answer: D. Nitrogen
Nitrogen is an inert gas that prevents the oxidation of fats and oils. It is commonly flushed into potato chip packets to keep them fresh. This helps in avoiding the development of rancidity in food.
The reaction $CaO + H_2O \rightarrow Ca(OH)_2$ is an example of?
Correct Answer: C. Combination reaction
Quicklime reacts vigorously with water to produce slaked lime in a combination reaction. This reaction releases a significant amount of heat energy. Slaked lime is frequently used for whitewashing walls.
Which of the following describes the electrolysis of water?
Correct Answer: D. Decomposition reaction
Electrolysis uses electricity to break down water into hydrogen and oxygen gases. Since one substance splits into two, it is a decomposition reaction. The ratio of hydrogen to oxygen produced is 2:1 by volume.
What happens during a thermal decomposition reaction?
Correct Answer: C. Heat is absorbed
Thermal decomposition requires the input of heat to break down a compound. Because energy is absorbed, these reactions are considered endothermic. Heating calcium carbonate to produce lime is a common industrial example.
In the reaction $CuO + H_2 \rightarrow Cu + H_2O$, which substance is oxidized?
Correct Answer: A. Hydrogen
Hydrogen is oxidized because it gains an oxygen atom to become water. In the same reaction, copper oxide is reduced to copper by losing oxygen. This simultaneous occurrence makes it a classic redox reaction.
Which of the following is required for the process of photosynthesis?
Correct Answer: B. Carbon dioxide
Plants take in carbon dioxide from the atmosphere to synthesize glucose. This reaction also requires sunlight and chlorophyll to proceed. It is an endothermic process that releases oxygen as a byproduct.
What is the chemical name of the rust formed on iron surfaces?
Correct Answer: A. Hydrated ferric oxide
The correct answer is 'Hydrated ferric oxide'. Rust is a reddish-brown flaky substance formed by the reaction of iron with moisture and oxygen. Its chemical formula is generally represented as $Fe_2O_3 \cdot xH_2O$. Preventing rust is often achieved through painting or galvanization.