Question

X and y are metal nitrates x on heating liberates o2 only but y on heating liberates no2 and o2 x and y are respectively

Answer 1

X is Potassium nitrate or Sodium Nitrate (Monovalent alkali metals)  and Y is Nitrates of elements like Li, Hg, etc.

• All group 1 metal nitrates (except LiNO3 ) give metal nitrite and oxygen.

• Among monovalent metals AgNO3  is an exception as it decomposes on heating to give free metal and nitrogen dioxide.
• All divalent and trivalent metals (except Hg(NO3 )2 ) decompose on heating to give metal oxide, nitrogen dioxide and oxygen.
• Other examples are Mg, Ca, Al, Pb, etc.