Questions

A redox reaction is a type of reaction which involves transfer of electrons among two species. This reaction is also called oxidation-reduction reaction.

In oxidation process, there is an increase in oxidation state of an atom, ion or molecule by losing the electrons.

In reduction process, there is a decrease in oxidation state of an atom, ion or molecule by accepting the electrons.

1)

In this reaction, Ba undergoes oxidation and Cl undergoes reduction.
This reaction is redox reaction.
In this reaction, oxidation number of Ba increases from 0 to +2 . So, Ba undergoes oxidation. The oxidation number of Cl decreases from 0 to -1. So, Cl undergoes reduction.

2) 

From this above reaction, it is clear that Aluminum undergoes oxidation and silver undergoes reduction.
Due to this, this reaction is redox reaction.

In this reaction, oxidation number of Aluminum increases from 0 to +1. So, aluminum undergoes oxidation. The oxidation number of silver decreases from +1 to 0. So, silver undergoes reduction.

3)

In this reaction, Mg undergoes oxidation and Br undergoes reduction.
This reaction is redox reaction.
The reactions 1, 3 and 4 are redox reactions.
In this reaction, oxidation number of Mg increases from 0 to +2 . So, Mg undergoes oxidation. The oxidation number of Br decreases from 0 to -1 . So, Br undergoes reduction.

Hence all the above reactions are redox reactions.

Farsightedness is more properly called Hyperopia.

In the above given options, Retrovirus is the only virus which is not associated with cancer. Here the viruses which are associated with different types of cancer. They are:

Hepatitis virus which is associated with Liver cancer

Papillomavirus which is associated with Cervical cancer

Epstein-Barr virus which is associated with Burkitt's lymphoma.

The law of conservation of energy is a law of science which states that energy can neither be created nor destroyed - only converted from one form of energy to another.

In 1842, Julius Robert Mayer discovered the Law of Conservation of Energy.

In the light of competition, it may be seen that competitors may initiate price changes. If the cutting off on prices does not affect the company, then the current pricing strategy itself can be continued to maintain the profitability of the company. However if the price change on one firm is affecting the other, then it can:

a.reduce the product price at par with competitors’ price or below competitors’ price

or

b. Provide added advantage to the existing product like better quality, or ‘a buy one get one free’ offer.

or

c.Provide better quality of the product at a higher price thereby not being at par with the competitors.

At any given speed, momentum is directly proportional to mass of an object.