An excess 0.10moldm^-3 HCl was poured into a big beaker containing 2g of limestone. The unreacted acid required 25cm³ of 0.10moldm^-3 potassium carbonate to neutralize it. What was the original volume of the acid? [Ca = 40, C = 12, 0 = 16]

• A.250cm³
• B.260cm³
• C.400cm³
• D.450cm³