CLASS 10 SCIENCE IMPORTANT QUESTION ANSWERS BY AARISH SIR

 CBSE CLASS 10 SCIENCE IMPORTANT QUESTION ANSWERS

BY AARISH SIR

1. What does ethanol look like? What happens when it’s heated with strong sulphuric acid? Describe it with a chemical equation, explaining the role of sulphuric acid.

2. Explain the differences between making esters and soap. Mention one use for esters and one for sporenification.

3. Why is reproduction crucial for living beings? Give three reasons to support this statement.

4. Define vegetative propagation and outline two benefits and two drawbacks of this method.

5. How does a glass prism split white light, and what did Newton demonstrate using identical prisms? Include a simple diagram.

6. Propose two ways to create awareness in your neighbourhood about water conservation.

7. Define ‘dispersion of white light’ and illustrate it using a labeled diagram. Explain why identical prisms are essential.

8. Describe how Rhizopus reproduces using spores. Provide an easy explanation.

9. Explain esterification using a chemical equation. Describe an activity to demonstrate esterification simply.

10. Define vegetative propagation again and highlight two advantages and two disadvantages of this method.

ANSWERS

1. Ethanol is a colorless liquid. When heated with strong sulphuric acid, it undergoes dehydration to form ethene, water, and sulphuric acid acts as a catalyst. The chemical equation is: C2H5OH → C2H4 + H2O. Here, sulphuric acid removes the elements of water, promoting the formation of ethene.

2. Making esters involves combining an alcohol and carboxylic acid, producing pleasant-smelling compounds. Soap, on the other hand, is produced through saponification of fats with an alkali, yielding cleaning agents. Esters find use in perfumes, while saponification is essential in soap production.

3. Reproduction is crucial for species survival, genetic diversity, and adaptation to changing environments. It ensures the continuity of life, facilitates evolution, and maintains ecological balance.

4. Vegetative propagation is a type of asexual reproduction. Benefits include the preservation of desirable traits and rapid propagation. Drawbacks involve reduced genetic diversity and susceptibility to diseases affecting the entire clone.

5. A glass prism splits white light into its constituent colors through dispersion, creating a spectrum. Newton demonstrated this using identical prisms by recombining the dispersed colors back into white light, illustrating that prisms don't alter the nature of light but rather separate it based on its varying wavelengths.

6. To raise awareness about water conservation in your neighborhood, organize workshops on efficient water usage and distribute pamphlets with tips. Additionally, host community events like tree planting to emphasize the connection between trees, water retention, and conservation.

7. Dispersion of white light is the separation of light into its different colors. Illustrated in a diagram, when white light passes through a prism, it bends, and different colors emerge due to varying wavelengths. Identical prisms are crucial to ensure accurate results and consistent dispersion in experiments or applications.

8. Rhizopus reproduces through spores, a process called sporangiospores formation. Specialized structures, sporangia, produce and release spores, which then germinate to form new Rhizopus colonies. This simple reproduction cycle ensures the fungus's survival and dispersal.

9. Esterification involves combining an alcohol and carboxylic acid to produce an ester and water. Represented by the chemical equation: Alcohol + Carboxylic Acid → Ester + Water. For a simple demonstration, mix alcohol and a carboxylic acid with a catalyst (acid), and observe the formation of an ester, often with a distinct odor.

10. Vegetative propagation is a method of asexual reproduction. Advantages include the preservation of desirable traits and quicker plant production. Disadvantages encompass reduced genetic diversity and vulnerability to diseases affecting the entire clone.