Exams

As water is cooled from 4 deg C to 0 deg C, the water reaches its freezing point and starts forming ice crystals. Then the volume of that ice cubes increases and its density decreases. Hence, it is the reason that ice will float on water as ice has less density than the water.

The current infection control guidelines from the CDC (The Centers for Disease Control and Prevention) are called Standard or Universal Precautions.

The temperature at which water boils depends mainly on air pressure.

The American Planning Association (APA) has announced this year's international excellence award for the Bhubaneswar smart city project.

The award called Pierre L'Enfant International Planning Excellence Award 2017 will be given on May 8 in New York city.

This is the first time in the 50 years history of APA's annual award programme that an Indian city has been recognised for its planning efforts.

ACTH means Adrenal Corticotrophic Hormone.

CRH - Corticotrophin Releasing Hormone produced by hypothalamus stimulates the pituitary gland to release the ACTH which in turn produces corticosteroid hormones by adrenal glands.

Hence, the given statement is TRUE.

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.