On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (Black), oxygen gas and a brown gas X is formed
(a) Write a balanced chemical equation of the reaction.
(b) Identify the brown gas X evolved.
(c) Identify the type of reaction.
(d) What could be the pH range of aqueous solution of the gas X ?

Explanation

`(a) underset(underset("nitrate")("Copper"))(2Cu(NO_(3))_(2))overset("Heat")to underset(underset(underset("(black)")("oxide"))("Copper"))(2CuO)underset("Oxygen")(O_(2))+underset(underset(underset(underset("(X)")("(brown)"))("dioxide"))("Nitrogen"))(4NO_(2))`
(b) X is nitrogen dioxide gas `(NO_(2))`.
(c) This is a thermal decomposition reaction.
(d) The aqueous solution of the gas is acidic because it is an oxide of a non-metal, so its pH range would be in between 1 to 7 .