The Sodium Chloride Structure

The Sodium Chloride Structure

General Notes

NaCl has a cubic unit cell. It is best thought of as a face-centered cubic array of anions with an interpenetrating fcc cation lattice (or vice-versa). The cell looks the same whether you start with anions or cations on the corners. Each ion is 6-coordinate and has a local octahedral geometry

 

Structure

Shown below are two crystallographic planes in NaCl. Notice that the (111) plane is hexagonally closest packed

 

kmno4

Potassium Permanganate: Structure and Formula

Potassium permanganate is not as popular as other chemical compounds, but we probably encounter it more often than we think. Potassium permanganate, also known as permanganate of potash or Condy's crystals, is a chemical compound consisting of two ions: a potassium ion and a permanganate ion.

The physical state of potassium permanganate is an odorless solid, and they look like dark purple or bronze colored crystals. If we dissolve these crystals in water, the solution becomes purple in color. Potassium permanganate is able to oxidize many substances, so it is very well known as a strong oxidizing agent, a substance that accepts or takes electrons from other substances.

Uses Of Potassium Permanganate

Potassium permanganate has various uses in various fields, such as water treatment, organic chemistry, analytical chemistry, and even in survival situations. In this section, we will discuss the various uses of potassium permanganate.

 Properties of Potassium permanganate (KMnO₄)


1. Potassium permanganate (KMnO₄): Action of HeatPotassium permangante on strong heating gives potassium manganate, manganese dioxide and oxygen.

2 KMnO₄ ----------> K₂MnO₄ + MnO₂ + O₂

2. Oxidising properties of Potassium permanganate (KMnO₄)

Potassium permanganate is a powerful oxidizing agent in alkaline or acidic solution. The relevant half reactions are:

1. Alkaline medium (pH > 7)

MnO₄^- + 2H₂O + 3 e^- ----------> MnO₂ + 4OH^-


2. Acidic medium (pH <7)

MnO₄^- + 8H⁺ + 5e^- ----------> Mn²⁺ + 4H₂O



A few important oxidizing reactions of Potassium permanganate (KMnO₄)


1. In acidic medium potassium permanganate oxidizes green ferrous salts to yellow ferric salts

MnO₄^- + 8H⁺ + 5Fe²⁺ ----------> 5Fe³⁺ + Mn²⁺ + 4H₂O


2. in acidic medium potassium permanganate oxidizes oxalic acid or oxalate salts to CO₂and water2 MnO₄^- + 16H⁺ + 5 C₂O₄^2- -------------> 2 Mn²⁺ + 10 CO₂ + 8 H₂O


3. In acidic medium potassium permanganate oxidizes nitrites to nitrate.


2 MnO₄^- + 6 H⁺ + 5 NO₂^- -------------> 2 Mn²⁺ + 5 NO₃^- + 3 H₂O


4. In acidic medium potassium permanganate oxidises iodides to iodine.

2 MnO₄^- + 16 H⁺ + 1 OI^- ----------> 2 Mn²⁺ + 8 H₂O + 5 I₂


5. In alkaline medium potassium permanganate oxidizes iodides to iodates .

2 MnO₄^- + H₂O + I^- ------------> IO₃^- + 2MnO₂ + 2 OH^-

defn of kinetics

Definition of kinetics

1. 1a :  a branch of science that deals with the effects of forces upon the motions of material bodies or with changes in a physical or chemical systemb :  the rate of change in such a system
2. 2 :  the mechanism by which a physical or chemical change is effected

volumetric analysis

Q:

What is volumetric analysis used for?

A:

Quick Answer

Volumetric analysis is used to determine the value of a substance by using the volume of a known substance within the compound. This process, also known as titrimetric analysis, is most commonly used by chemists to quantify unknown concentrations in chemical reactions.

• What is titration?

• What are some common types of solutes?

• What is a dehydrating agent?

Full Answer

The process of volumetric analysis was developed by the French chemist Jean-Baptiste Alfred Dumas to identify the concentration of nitrogen in biological compounds. He applied the method by burning a fragment of the compound to convert the nitrogen to gas and allow it to build up in a graduated cylinder. Since Dumas' development of volumetric analysis in the mid-19th century, chemists have adapted the process for nearly all chemical compounds.