$\mathrm{CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O + ?}$. The missing product is—

Question

Accepted Answer

$\mathrm{CO_2}$

Answer

$\mathrm{H_2}$

Answer

$\mathrm{O_2}$

Answer

$\mathrm{NH_3}$

CaCO3+2HCl→CaCl2+H2O+?\mathrm{CaCO_3 + 2HCl \rightarrow CaCl_2 + H_2O + ?}CaCO3​+2HCl→CaCl2​+H2​O+?. The missing product is—