--%>
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 : Problem on Neutralization What weight

    What weight of hydrated oxalic acid should be added for complete neutralisation of 100 ml of 0.2N - NaOH solution? (a) 0.45 g  (b)0.90 g  (c) 1.08 g  (d) 1.26 g      Answer

    		•
  • Q : What is Henry law constant and its

    1. The units of Henry Law constant are same as those of pressure, i.e. torr or h bar. 2. Different gases have dissimilar values of Henry law constant. The values of KH for some gases in water are given in tabl

    		•
  • Q : Molarity of solution Help me to go

    Help me to go through this problem. When 7.1gm Na2SO4 (molecular mass 142) dissolves in 100ml H2O , the molarity of the solution is: (a) 2.0 M (b) 1.0 M (c) 0.5 M (d) 0.05 M

    		•
  • Q : What are Ethers and its types? Ethers

    Ethers are the compounds with general formula or CnH2n+

    		•
  • Q : Simulate the column in HYSYS The

    The objective of this work is to separate a binary mixture and to cool down the bottom product for storage. (Check table below to see which mixture you are asked to study). 100 kmol of feed containing 10 mol percent of the lighter component enters a continuous distillation column at the m

    		•
  • Q : Changes in matter law of chemical

    changes in matter law of chemical combination

    		•
  • Q : Depression in the freezing point When

    When 0.01 mole of sugar is dissolved in 100g of a solvent, the depression in freezing point is 0.40o. When 0.03 mole of glucose is dissolved in 50g of the same solvent, depression in the freezing point will be:(a) 0.60o  (b) 0.80o

    		•
  • Q : What is cannizaro reaction? Explain

    Aldehydes which do not have  -hydrogen atom, such as formaldehyte and benzaldehyte, when heated with concentrated (50%)alkali solutio

    		•
  • Q : Extensive property Choose the right

    Choose the right answer from following. Which one of the following is an extensive property: (a) Molar volume (b) Molarity (c) Number of moles (d) Mole fraction

    		•
  • Q : What are methods of phenol preparation

    Phenol was initially obtained by fractional distillation of coal

    		•