Q22 of 53 Page 1

Give reasons for the following:

(i) (CH3)3P=O exists but (CH3)3N=O does not


(ii) ) Oxygen has less electron gain enthalpy with negative sign than sulphur.


(iii) H3PO2 is a stronger reducing agent than H3PO3


(i) (CH3)3P=O exists because phosphorous has vacant d- orbital and so it can extend its covalency beyond 4 but in case of (CH3)3N=O does not exist because nitrogen does not have vacant d- orbital and its covalency cannot become more than 4.


(ii) This is due to very small size of Oxygen atom and the large repulsion between electrons in relatively small 2p sub-shell in comparison to sulphur. So, oxygen has less negative electron gain enthalpy than sulphur


(iii) In H3PO2 there are 2 P–H bonds, whereas in H3PO3 there is 1 P–H bond. So, H3PO2 is a better reducing agent than H3PO3


More from this chapter

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20

The following data were obtained during the first order thermal decomposition of SO2Cl2 at a constant volume:

SO2Cl2(g) → SO2(g) + Cl2(g)


Experiment Time/ s-1 Total pressure/atm


1 0 0.4


2 100 0.7


Calculate the rate constant.


(Given: log 4 = 0.6021, log 2 =0.3010)


 21

What are emulsions? What are their different types? Give one example of each type.

 23

(i) Write the IUPAC name of the complex [Cr(NH3)4Cl2]Cl.

(ii) What type of isomerism is exhibited by the complex [Co(en)3]3+?


(en= ethane-1,2-diamine)


(iii) Why is [NiCl4]2- paramagnetic but is [Ni(CO)4] is diamagnetic?


(Atomic No: Cr=24, Co=27,Ni=28)


 24

(a) Draw the structures of major monohalo products in each of the following reactions:


(b) Which halogen compound in each of the following pairs will react faster in SN2 reaction:
(i) CH3Br or CH3I


(ii) (CH3)3C-Cl or CH3-Cl