Chemistry Questions

The sodium fusion test, or Lassaigne's test, is used in elemental analysis for the qualitative determination of the presence of foreign elements, namely halogens, nitrogen, and sulphur, in an organic compound. It was developed by J. L. Lassaigne.Silver fluoride is soluble in water and does not precipitate and thus this method cannot be used for detection of fluorine.

Phencyclidine (PCP) is a drug used for its mind-altering effects. It is also known as Angel dust. As a recreational drug, it is typically smoked, but may be taken by mouth, snorted, or injected. It may also be mixed with cannabis or tobacco.

Causes and Effects ::

* PCP may cause hallucinations, distorted perceptions of sounds, and violent behavior.

* Its effects include seizures, coma, addiction, and an increased risk of suicide.

Lime is sometimes applied to soil in order to increase the acidity of the soil.

Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

These Colloid substances consists of ultramicroscopic particles of one substance dispersed through another substance from which we cannot separate them.

Sugar water is not a colloid and it is a solution in which we can separate them.

When an atom loses an electron it becomes a positive ion by acquiring negatively charged. When it loses electron, the atom's radius also decreased.

An ionic bond is a chemical bond between two atoms in which one atom seems to donate its electron to another atom.

Here in the given compounds, the compound that contains ionic bond is CaO, Calcium oxide.

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.