(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 + SbF5 5mark
a) (i)A = NO2 , B = N2O4 (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