--%>
Assignment Help - homework help

Describe characteristics of halides and oxides.

Halides characteristics

(i) These trihalides are mainly covalent with the exception of BiF3 which is ionic.

(ii) The ionic character of trihalides increases in going down the group.

(iii) Like hydrides, these trihalides have pyramidal structure.

(iv) These trihalides except NX3 can be easily hydrolysed by water.

The inability of trihalides of N to hydrolyse is attributed to the non-availability of vacant d-orbitals in nitrogen.

(v) The trihalides of P, As, Sb (especially fluorides and chlorides) act as Lewis acids and combine with Lewis bases

PF3 + F2  1973_halides and oxides.png  PF5

SbF3 + 2F-  1973_halides and oxides.png   [SbF5]2-

(vi) The pentahalides in general, have less thermal stability as compared to trihalides.

(vii) All the pentahalides act as Lewis acids. It is because the central atom can easily accept the halide ions due to presence of vacant d-orbital and can extend their co-ordination number.

(viii) PCl5 exists as molecule in gaseous state but in solid state it exists as [PCl4]+[PCl6]- and is ionic in nature. PBr5, PI5 also exists in the ionic form in solid state.

Reactivity towards oxygen: the elements of this group combine with oxygen directly or indirectly to form a large number of different types of oxides.

Nature of oxides

All the oxides of nitrogen except NO and N2O and phosphorus are strongly acidic: oxides of arsenic are weakly acidic; oxides of antimony are amphoteric and those of bismuth are weakly basic.

Reason: the change in character from acidic to basic can be explained on the basis of the size of atoms. As the size of nitrogen atom is small and it has a strong positive field, it interacts with water more strongly pulling the electron pair between O - H bond and thus release of H+ ions.

However, this tendency diminishes with the increase in size and therefore decreases the acidic character or conversely increases the basic character.

As far as the stability of the oxides is connected it is found that oxides having elements in the higher oxidation state become less stable as we move down to group. This is because of the import pair effect.

   Related Questions in Chemistry

  • Q : Polyhalogen compounds we need 10

    we need 10 examples for the polyhalogen compounds....please help me....need it urgently...

    		•
  • Q : Amount of glucose in blood What is the

    What is the normal amount of glucose in 100ml of blood (8–12 hrs after meal) is: (i) 8mg (ii) 80mg (iii) 200mg (iv) 800mg Choose the right answer from above.

    		•
  • Q : Pressure Phase Diagrams The occurrence

    The occurrence of different phases of a one component system can be shown on a pressure temperature. The phases present in a one line system at various temperatures can be conveniently presented on a P- versus-T diagram. An example is pro

    		•
  • Q : What is laser and explain its working?

    Laser action relies on a non-Boltzmann population inversion formed by the absorption of radiation and vibrational deactivation that forms a long lived excited electronic state. An excited state molecule can move to a lower energy state or return to the

    		•
  • Q : What do you mean by the term Organic

    What do you mean by the term Organic Chemistry? Briefly define the term?

    		•
  • Q : Basic concepts Determination of correct

    Determination of correct mol. Mass from Roult's law is applicable to :

    		•
  • Q : Atmospheric pressure Give me answer of

    Give me answer of this question. The atmospheric pressure is sum of the: (a) Pressure of the biomolecules (b) Vapour pressure of atmospheric constituents (c) Vapour pressure of chemicals and vapour pressure of volatile (d) Pressure created on to atmospheric molecules

    		•
  • Q : Calculating weight of acid Give me

    Give me answer of this question. The formula weight of H2SO4 is 98. The weight of the acid in 400mi of solution is: (a)2.45g (b) 3.92g (c) 4.90g (d) 9.8g

    		•
  • Q : Explain structure basicity of amines.

    Basic character of amines is related to their structural arrangement. Basic strength of amines depends on the relative ease of formation of the corresponding cation by accepting a proton from the acid. Greater the stability of cation is, more is basic strength of amine.Alkyl a

    		•
  • Q : Problem based on molarity Choose the

    Choose the right answer from following. The molarity of a solution of Na2CO3 having 10.6g/500ml of solution is : (a) 0.2M (b)2M (c)20M (d) 0.02M

    		•