Q15 of 26 Page 1

Account for the following:

(a) Inter-halogen compounds are more reactive than pure halogens.


(b) Nitrogen is less reactive at room temperature.


(c) Reducing character increases from NH3 to BiH3.


(a) Inter-halogen compounds are more reactive than pure halogens as the X-X’ bond in inter-halogen compounds is weaker than the X-X bond in halogens(except Fluorine).


(b) Nitrogen is less reactive at room temperature due to presence of triple bond between the two nitrogens which requires more energy to break the bonds. But as the temperature increase nitrogen readily reacts with metals and non-metals to form nitrides.


(c) The ability to donate hydrogen or electrons is a good character of a reducing agent. In group 15 the reducing character increases down the group as the electronegativity decreases( can easily donate hydrogen) and size increases( outermost electrons are held loosely due to shielding of nucleus by inner electrons).


More from this chapter

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13

For a first order reaction, show that time required for 99% completion is double of the time required for the completion of 90% of reaction.

OR


The rate constant of a first order reaction increases from 4 x 10-2 to 24 x 10-2 , when the temperature changes from 300 K to 350 K. Calculate the energy of activation (Ea). [ Given: log 2 = 0.3010, log 3 = 0.4771, log 4 = 0.6021, log 6 = 0.7782; R = 8.314 J/K/mol]


 14

(a) Indicate the principle behind the method for the refining of zinc.

(b) Account for the following:


(i) It is advantageous to roast sulphide ore to oxide before reduction.


(ii) Zinc oxide can be reduced to metal by heating with carbon but not Cr2O3.


 16

(a) For the complex [CoF6]3-, write the hybridization type, magnetic character and spin nature of the complex. (Atomic no. of Co = 27)

(b) Why is the complex [Co(en)3]3+ more stable than [CoF6]3-?


 17

(a) How do you convert the following?

(i) Prop-1-ene to propan-2-ol.


(ii) Bromobenzene to 2-bromoacetophenone


(b) Alkyl halides though polar, are immiscible with water. Why?