Physical properties of aryl halides

-
Aryl halides :- 

State :  These are generally liquids at room temperature.

Melting point and boiling point : In aryl halides two forces , i.e dipole - dipole interaction and Vander waals forces of attraction generally decide it's physical properties .

(a) - The melting point and boiling point of aryl halides are nearly the same as those of haloalkanes with the same number of carbon atom.
(b) - For the same aryl group , the melting point and boiling point increase as the size of halogen atom .
I.e.  iodo arenes > bromo arenes > chloro arenes  > iodo arenes .
(Increase of van der waals forces of attraction)
(c) - for the same halogen atom the melting point and boiling point are increase when the size of aryl group increase .
(d) - Among the dialogue derivatives the boiling points are almost the same but the melting points of p - isomer is more than those of Ortho and meta isomers . It is because , due to symmetrical nature of p - isomer, the molecules pack more well in Crystal lattice than ortho and meta isomers . Therefore , attracting force and more in p - isomer which result in higher melting point than it's Ortho and meta isomers.

Solubility :  Aryl halides are insoluble in water . Because they don't form hydrogen bonds with water nor they can break the H - bond already present in water because of its less polar character . However they are soluble in low polar organic solvent like benzene , ether , chloroform etc .

Density : Aryl halides are heavier than water and their density generally increase from fluorobenzene iodo benzene .

Popular posts from this blog

Siemens Ozoniser how Siemens Ozoniser work

-
Image
Siemens Ozoniser:  This Ozoniser consist of two co-axial glass tubes fused together at one end. The outer side of the outer glass tube and the inner side of the inner glass tube are finally coated with tin foils as shown in the figure given below.  (Siemens Ozoniser)->2                                                     (Siemens Ozoniser)->1 These tin foil are connected  to the induction coil for supply of silent electric discharge. Pure and dry oxygen gas is passed into the apparatus through annular space. The gas is then subjected to the action of silent electric discharge where oxygen gets converted into ozone. The ozonised oxygen then comes out  of the apparatus through the outlet of the Ozoniser. (Siemens Ozoniser)->2
Read more

Rutile structure

-
Rutile structure: The radius radio is in the range 0.73 to 0.41. in rutile (TiO²) each Ti⁴+ ion is octahedrally surrounded by six O²- ions whereas each other O²- ion is surrounded by only three Ti⁴+ ions arranged at the tree corners of a plane triangle. The Co-ordination number of Ti⁴+ and O²+ ions are 6 and 3, respectively. It is not exactly a close packed structure. Ti⁴+ ions in rutile may however, be considered as forming a sufficiently distorted body centred cubic lattice.           Example  compounds  having radius ratio below 0.41 are SiO² and BeF² but these are only a few. The Co-ordination number of Si⁴+ and Be²+ is four and that of O²- is two. However, these are appreciably co-valent.
Read more

F - block element What are f - block elements

-
What are F - Block Elements - F - block elements are consist of Lanthanides and Actinides. In Lanthanides, they are 14 element immediately following Lanthanum (57) from cerium (58) to lutecium (71) . These 14 element are called Lanthanides . These Lanthanides belong to first inner transition series .           In Actinides , these are also 14 elements immediately following Actinium (89) starting from Thorium (90) to lawrencium (103) . The element from Th (90) to Lr (103) are called Actinides . They belong to second inner transition series.
Read more