Class 10 Science Carbon and Its Compound: NCERT Solutions for Question 12

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

Outline a project which aims to find the dominant coat colour in dogs.

Draw the structure for the following compounds.                

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

*Are structural isomers possible for bromopentane?

A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?

How is the sex of the child determined in human beings?

(a)  What property do all elements in the same column of the Periodic Table as boron have in common?
(b)  What property do all elements in the same column of the Periodic Table as fluorine have in common?

Calculate the number of electrons constituting one coulomb of charge.

What is an homologous series? Explain with an example.

A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?

Why is variation beneficial to the species but not necessarily for the individual?

The magnetic field in a given region is uniform. Draw a diagram to represent it.

Give an example of a double displacement reaction other than the one given in activity 1.10.

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

In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better’ body design? Why or why not?

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

How much energy is given to each coulomb of charge passing through a 6 V battery?

What are the different methods of contraception?

What is the difference between displacement and double displacement reactions? Write equations for these reactions.

How does reproduction help in providing stability to populations of species?

Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.