C-04-Q094mediumsingle_mcqCaCO3\mathrm{CaCO_3}CaCO3 + 2HCl →aCaCl2+H2O+CO2\mathrm{CaCl_2 + H_2O + CO_2}CaCl2+H2O+CO2bCaCl+H2+O2\mathrm{CaCl + H_2 + O_2}CaCl+H2+O2cCa(OH)2+Cl2\mathrm{Ca(OH)_2 + Cl_2}Ca(OH)2+Cl2dCaCl2+H2\mathrm{CaCl_2 + H_2}CaCl2+H2