Respuesta :
So,
All you need to do is read the physical states ( ) to determine the answer.
CuCO3 is solid.
HCl is in aqueous solution.
CuCl2 is in aqueous solution.
H2O is liquid.
CO2 is gas.
It is then easy to see that option D is true. CuCO3 is the solid reactant, and CO2 is the gas product.