X grams of sodium carbonate (Na2CO3) (s) reacted completely with 30cm of dilute hydrochloric acid to product 672cm³ of carbon dioxide gas at S.T.P (1 mole of gas occupies 22.4L at S.T.P, C = 12.0, 0 = 16.0, Na = 23.0 (1mark) (1mark) (1) Write the equation for the reaction (ii) Calculate the concentration of the acid in moles per litre (2marks)