On heating, lead (II) nitrate gives a brown gas 'A'. The gas 'A' on cooling changes to colourless solid 'B'. Solid 'B' on heating with NO changes to a blue solid 'C'. Identify 'A', 'B' and 'C' and also write reactions involved and draw the structures of 'B' and 'C'.

On heating, lead (II) nitrate gives a brown gas 'A'. The gas 'A' on co

1.	On heating, lead (II) nitrate gives a brown gas 'A'. The gas 'A' on cooling changes to colourless solid 'B'. Solid 'B' on heating with NO changes to a blue solid 'C'. Identify 'A', 'B' and 'C' and also write reactions involved and draw the structures of 'B' and 'C'.
Answer» Solution :(i) Since lead (II) NITRATE on heating gives a brown gas 'A', therefore, gas 'A' must be nitrogen dioxide `(NO_(2))`. `UNDERSET("Lead (II) nitrate")(2Pb(NO_(3))_(2)) overset(DELTA, 673 K)RARR 2 PbO + underset("Brown gas (A)")(4 NO_(2))+O_(2)` (ii) Thre brown gas 'A' on cooling dimerises to give a colourless solid 'B', therefore 'B' must be `N_(2)O_(4)` (dinitrogen tetroxide). `2 NO_(2) underset("On heating")overset("On cooling")(hArr) underset("Colourless solid (B)")(2N_(2)O_(4))` (iii) Since colourless solid 'B' on heating with NO, gives a blue solid 'C', therefore 'C' muct be dinitrogen trioxide. `2 NO + underset("Colourless (B)")(N_(2)O_(4)) rarr underset("Blue solid (C)")(2 N_(2)O_(3))` Thus, `A = NO_(2), B = N_(2)O_(4) and C = N_(2) O_(3)`.