Question

salt which leaves black residue on heating
a)lead carbonate
b)copper nitrate
c)calcium carbonate
d)magnesium carbonate​

Answer 1

Answer:

Option B is the correct answer.

Answer 2

2Cu(NO3)2 (s) -------> 2CuO (s)+ 4NO2 (g) + O2 (g)

The brown gas is nitrogen(IV) oxide NO2, the black residue is copper(II) oxide CuO.

b) Copper nitrate is the answer