Calculate the number of moles of calcium chloride, CaCl, that can be obtained from 25g of limestone, CaCO in the presence of excess hydrogen chloride, HCl.(Ca=40, C=12,O=16,H=K,Cl=35.5). Equation of reaction: CaCO+2HCL-CaCl+HO+CO

Limestone is CaCO3. Calcium chloride is CaCl2.

The correct equation is below and not what you wrote.
CaCO3 + 2HCL ==> CaCl2 + H2O + CO2
molar mass CaCO3 = 100
mols CaCO3 in 25 grams = 25/100 = 0.25
For every 1 mole CaCO3 you get 1 mole CaCl2; therefore, you will get 0.25 moles CaCl2.