Question

The stoichiometric relationship between the reactants and products of an aqueous reaction can be used to determine different kinds of information about a reaction, such as the volume of a given molarity reactant required to produce a certain amount of product.

Hydrochloric acid (HCl) reacts with sodium carbonate (Na2CO3), forming sodium chloride (NaCl), water (H2O), and carbon dioxide (CO2). This equation is balanced as written:

2HCl(aq)+Na2CO3(aq)→2NaCl(aq)+H2O(l)+CO2(g)

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a) What volume of 2.00 M HCl in liters is needed to react completely (with nothing left over) with 0.250 L of 0.300 M Na2CO3?

Express your answer numerically in liters.

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b) A 373-mL sample of unknown HCl solution reacts completely with Na2CO3 to form 19.1 g CO2. What was the concentration of the HCl solution?

Express the molar concentration numerically.

Answer 1

Reaction is

Na₂CO₃ + 2HCl   2 NaCl + H₂O + CO₂

caculate mole of Na₂CO₃

no. of mole = molarity volume of solution in liter

no . of mole of Na₂CO₃ = 0.300 M 0.250 = 0.075 mole of Na₂CO₃

Accoeding to reaction 1 mole of  Na₂CO₃ require 2 mole of HCl for complete reaction then to react with 0.075 mole of  Na₂CO₃ require = 0.075 2 = 0.150 mole of HCl

volume of HCl in liter = no. of mole / molarity = 0.150 / 2 = 0.075 liter of HCl

0.075 liter of HCl required.

b)

Na₂CO₃ + 2HCl   2 NaCl + H₂O + CO₂

molar mass of CO₂ = 44.01 gm then 19.1 gm CO₂ = 19.1/44.01 = 0.434 mole

according to reaction 2 mole of HCl produce 1 mole of CO₂ then to produce 0.434 mole of CO₂ required

0.434 2 = 0.868 mole of HCl

molarity = no. of mole / volume of solution in liter

molarity of HCl = 0.868 / 0.373 = 2.327 M

molarity of HCl = 2.327 M