Questions

Here, “to reach in time” should be used. Idiom in times mean, not late. with enough time, to be able to do something

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.

The potable water is the water, which is tested and safe for drinking purpose and cooking preparations. The water is tested and purified in industries. So, the potable water is costly.

Hence, Access to potable water is most heavily limited by money.

The Preamble was adopted with the constitution in the constituent assembly.

The Preamble proclaims the solemn resolution of the people of India to constitute India into a 'Sovereign socialist secular democratic republic'.

Electronegativity, is a chemical property that describes the tendency of an atom to attract a shared pair of electrons (or electron density) towards itself.