How halides and sulphides form in organic chemistry?, Chemistry

Halides 

Transition metals react with halogens at high temperatures to form halides. These reactions have very high activation energies; therefore, high temperatures are required to start these reactions. However, once the reaction starts, the heat liberated is sufficient to sustain the reaction. The order of reactivity of different halogens decreases as:

Fluorides are usually ionic whereas chlorides, bromides and iodides are predominantly covalent. The covalent character increase in atomic mass of the halogen. For example, CuF2 is ionic while CuCl2 and CuBr2 are covalent consisting of infinite chains. Co-ordination number of copper in these compounds is six.

Fluorine brings about the highest oxidation state of the metal. This is due its small size and high electronegativity. Halides of metals in higher oxidation states are relatively unstable and get hydrolysed easily. For example,
                                         
TiCl4 + 2H2O  1729_halides.png  TiO2 + 4HCl

Sulphides

Sulphides of transition metals are prepared either by direct combination of sulphur with metals or by the reaction of H2S or Na2S with the solution of their salts. In sulphides, the oxidation state of metal is generally low because sulphur is a weak oxidising agent. These sulphides are generally coloured or black. For example, NiS, CoS and CuS are black, MnS is light pink and CdS is yellow. They are insoluble in water.

Example: classify the following oxides as acidic, basic and amphoteric:
                         
MnO, MnO2, Mn2O3, Mn3O4, Mn2O7.

Solution: Acidic oxide : Mn2O7
               
Basic oxides : MnO, Mn2O3
      
Amphoteric oxides: Mn3O4, MnO2.

 

 

 

Posted Date: 6/25/2012 8:27:53 AM | Location : United States







Related Discussions:- How halides and sulphides form in organic chemistry?, Assignment Help, Ask Question on How halides and sulphides form in organic chemistry?, Get Answer, Expert's Help, How halides and sulphides form in organic chemistry? Discussions

Write discussion on How halides and sulphides form in organic chemistry?
Your posts are moderated
Related Questions
What is the difference between reaction stoichiometry and composition stoiciometry?

In solid state chemistry the CN 2 2- ion shows constitutional isomerism. The free acids of both anions (at least in the gas phase) are known. Illustrate the structural formul


Explain in 100 words Congo Rubin Number?

What are total variables and degrees of freedom of a system of two components, when the number of phases is one, two, three etc.?  Ans:  For two - component systems, degree of

character table symmetry element ammonia

what is colloids

The difference between an ideal gas and a real gas is that real gases will not strictly follow the laws established for ideal gases, because of real-world characteristics. An idea


Which category matches with Ca(OH)2? - a. It is a Lewis acid. - b. It is a diprotic Br0nsted acid. - c. It is a salt. d. It is an Arrhenius base.