--%>
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 : Describe First Order Rate Equation The

    The integrated forms of the first order rate equations are conveniently used to compare concentration time results with this rate equation. Rate equations show the dependence of the rate of the reaction on concentration can be integrated to give expressions fo

    		•
  • Q : Problem related to molarity Provide

    Provide solution of this question. Increasing the temperature of an aqueous solution will cause: (a) Decrease in molality (b) Decrease in molarity (c) Decrease in mole fraction (d) Decrease in % w/w

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

    What do you mean by the term enzymes? Briefly illustrate it.

    		•
  • Q : Problem on solutions The 2N aqueous

    The 2N aqueous solution of H2S04 contains: (a) 49 gm of H2S04 per litre of solution (b) 4.9 gm of H2S04 per litre of solution (c) 98 gm of H2S04

    		•
  • Q : Molarity 20mol of hcl solution requires

    20mol of hcl solution requires 19.85ml of 0.01 M NAOH solution for complete neutralisation. the molarity of hcl solution

    		•
  • Q : Colligative property associated question

    Give me answer of this question. Which of the following is not a colligative property : (a)Optical activity (b)Elevation in boiling point (c)Osmotic pressure (d)Lowering of vapour pressure

    		•
  • Q : Finding Normality Can someone please

    Can someone please help me in getting through this problem. Concentrated H2SO4 has a density of 1.98 gm/ml and is 98% H2SO4 by weight. The normality is: (a) 2 N  (b) 19.8 N  (c) 39.6 N  (d) 98

    		•
  • Q : Haloalkane how haloalkane can be

    how haloalkane can be prepared by refluxing alcohol with hydrohalic acids

    		•
  • Q : Effect of addition of mercuric iodide

    Give me answer of this question. When mercuric iodide is added to the aqueous solution of potassium iodide, the:(a) Freezing point is raised (b) Freezing point is lowered (c) Freezing point does not change (d) Boiling point does not change

    		•
  • Q : Mole fraction of Carbon dioxide Choose

    Choose the right answer from following. If we take 44g of CO2 and 14g of N2 what will be mole fraction of CO2 in the mixture: (a) 1/5 (b) 1/3 (c) 2/3 (d) 1/4

    		•