NEET Chemistry The p-Block Elements (XII) Questions Solved


(a)When concentrated sulphuric acid was added to an unknown salt present in a test tube a brown gas (A) was evolved. This gas intensified when copper turnings were added to this test tube. On cooling, the gas (A) changed into a colourless solid (B).

(i)Identify (A) and (B). 

(ii)Write the structures of (A) and (B).

(iii)Why does gas (A) change to solid on cooling ?

(b)Arrange the following in the decreasing order of their reducing character :

                 HF,  HCl,  HBr,  HI 

(c)Complete the following reaction :

               XeF4 + SbF                                                                         5mark

a) (i)A = NO2    ,  B = N2O4                                                                   (1/2,1/2)mark

    (ii)                                                                                                   (1/2,1/2)mark


(iii)Because NO2 dimerises to N2O4 /  NO2  is an odd electron species.                 1mark

   b)HI > HBr > HCl > HF                                                                                  1mark

   c)XeF4 + SbF5 à [XeF3]+ [SbF6]-                                                                                 1mark

Difficulty Level:

  • 50%
  • 32%