--%>
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 : Vapour pressure of benzene Give me

    Give me answer of this question. The vapour pressure of benzene at a certain temperature is 640mm of Hg. A non-volatile and non-electrolyte solid weighing 2.175g is added to 39.08g of benzene. The vapour pressure of the solution is 600,mm of Hg . What is the mo

    		•
  • Q : Problem on mole fraction of glucose

    Provide solution of this question. While 1.80gm glucose dissolve in 90 of H2O , the mole fraction of glucose is: (a) 0.00399 (b) 0.00199 (c) 0.0199 (d) 0.998

    		•
  • Q : Question based on vapour pressure and

    Give me answer of this question. The vapour pressure of water at 20degreeC is 17.54 mm. When 20g of a non-ionic, substance is dissolved in 100g of water, the vapour pressure is lowered by 0.30 mm. What is the molecular weight of the substances: (a) 210.2 (b) 206.88

    		•
  • Q : Problem based on mole concept Choose

    Choose the right answer from following. An aqueous solution of glucose is 10% in strength. The volume in which mole of it is dissolved will be : (a) 18 litre (b) 9 litre (c) 0.9 litre (d) 1.8 litre

    		•
  • Q : Question based on normality Provide

    Provide solution of this question. A 5 molar solution of H2SO4 is diluted from 1 litre to 10 litres. What is the normality of the solution : (a) 0.25 N (b) 1 N (c) 2 N (d) 7 N

    		•
  • Q : What are diazonium salts? The diazonium

    The diazonium salts are represented by the general formula ArN2 +X where X- ion may be anion such as (Cl) ¨, B ¨r, HSO

    		•
  • Q : Colligative properties give atleast two

    give atleast two application of following colligative properties

    		•
  • Q : Explain gels and its various categories.

    Certain sols have the property of setting to a semi-solid, jelly-like form by enclosing the entire amount of liquid within itself when they are present at high concentrations. This process is called gelation and colloidal systems with jelly-like appearance are known as gels. Some common examples

    		•
  • Q : What are halogen oxoacids? Fluorine

    Fluorine yields only one oxyacid, hypo

    		•
  • Q : Electrons present in a benzene How

    How many electrons are present in a benzene?

    		•