Class 10 Science - Chapter Carbon and Its Compound NCERT Solutions | Explain the formation of scum when hard

Draw the structure for the following compounds.                

       (i)    Ethanoic acid             (ii)   Bromopentane*
       (iii)  Butanone                   (iv)   Hexanal.

*Are structural isomers possible for bromopentane?

What is an homologous series? Explain with an example.

How would you name the following compounds?

   (i)    CH₃  -- CH₂  -- Br

  (ii)

(iii) 

What will be the formula and electron dot structure of cyclopentane?

Explain the nature of the covalent bond using the bond formation in CH₃Cl.

Why are carbon and its compounds used as fuels for most applications?

How many structural isomers can you draw for pentane?

Explain the mechanism of the cleaning action of soaps.

What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?

How would you distinguish experimentally between an alcohol and a carboxylic acid?

Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

What is a good source of energy?

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

What changes can you make in your habits to become more environment-friendly?

What is the difference between a reflex action and walking?

What is the importance of DNA copying in reproduction?

If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?

Why should a magnesium ribbon be cleared before burning in air?

Define the principal focus of a concave mirror.

Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species?

How is the concentration of hydroxide ions (OH^-) affected when excess base is dissolved in a solution of sodium hydroxide?

What is a neutralisation reaction? Give two examples.

Which of the following lenses would you prefer to use while reading small letters found in a dictionary?

(a) A convex lens of focal length 50 cm.
(b) A concave lens of focal length 50 cm.
(c) A convex lens of focal length 5 cm.
(d) A concave lens of focal length 5 cm.

List two methods of producing magnetic fields.

A person needs a lens of power –5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?

Why do stars twinkle?

Which one of the following materials cannot be used to make a lens?

(a) Water        (b) Glass        (c) Plastic        (d) Clay

Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

Give an example of a metal which

  (i) is a liquid at room temperature.
  (ii) can be easily cut with a knife.
  (iii) is the best conductor of heat.
  (iv) is a poor conductor of heat.