Question

Acodofocation of sodium bicarbonate(NaHCO₃) produces carbon dioxide in a two-step process. The first step produces carbonic acid (H₂CO₃). Write and balance the molecular equation for the first step of the reaction of sodium bicarbonate with HF.

The second step is the decompostion of a carbonic acid to ccarbon dioxide. Write and balance the molecular equation for the second step.

Now write the overall net ionic equation for te acidification of NaHCO₃ to produce CO₂.

What is the molar ratio of CO₂ produced to NaHCO₃ decomposed?

What mass of CO₂ will be produced by the complete decompostion of 1346 mg of NaHCO₃?

Answer 1

Lets show the mechanism in two steps.

1).

NaHCO3 (s) + HF (aq) --- > H2CO3 (aq) + NaF (aq)

2).

H2CO3 (aq) --- > H2O (l) + CO2 (g)

Lets write overall reaction

NaHCO3(s) + HF(aq) --- > H2CO3 (aq) + NaF (aq)

H2CO3 (aq) --- > H2O (l) + CO2 (g)

-------------------------------------------------------------------

NaHCO3 (s) + HF (aq) --- > NaF (aq) + H2O (l) + CO2(g)

Complete ionic reaction:

NaHCO3 (s) + HF (aq) --- > Na+ (aq) + F- (aq) + H2O (l) + CO2 (g)

Net ionic equation :

NaHCO3 (s) + HF (aq) --- > Na+ (aq) + F- (aq) + H2O (l) + CO2 (g)

Molar ratio of CO2 produced to NaHCO3 decomposed is 1 : 1

Calculation of mass of CO2 formed from 1346 mg NaHCO3

Conversion of mass of NaHCO3 = 1346 mg x 1 g / 1000 mg

= 1.346 g

Calculation of moles of NaHCO3 = 1.346 g x 1 mol / 84.0059 g

= 0.016 mol

Moles of CO2 produced = 0.016 mol x 1 mol CO2 / 1mol NaHCO3

= 0.0160 mol CO2 produced

Mass of CO2 = 0.0160 mol CO2 x 44.009 g /mol

= 705 g

Mass of CO2 produced = 0.71 g