An Alkaline-Seltzer tablet contains exactly 100 mg of citric acid, H3C6H5O7, plus some sodium bicarbonate. What mass of sodium bicarbonate is required to consume 100. mg of citric acid by the following reaction?. H3C6H5O7 (aq) + 3 NaHCO3 (aq) = 3 H2O (l) + 3 CO2 (g) + Na3C6H5O7 (aq).

mass of NaHCO₃ = 0.126 g

Explanation:

balanced chemical equation

H₃C₆H₅O₇ (aq) + 3 NaHCO₃ (aq) → 3 H₂O (l) + 3 CO₂ (g) + Na₃C₆H₅O₇ (aq).

given data

moles of citric acid = 1 mol

mas of citric acid = 100 mg

mas of citric acid = 0.1 g

moles of sodium bicarbonate = 3 mol

mass of sodium bicarbonate = ?

Solution

1st we will find out the mole ratio of H₃C₆H₅O₇ and NaHCO₃ from balanced chemical equation

H₃C₆H₅O₇ : NaHCO₃

1 : 3

Now we find out number of moles of citric acid

moles = mass / molar mass

moles = 0.1 g / 192.124 g/mol

moles = 0.0005 mol

now we find out moles (x) of sodium bicarbonate needed for 0.0005 mol of citric acid

from the balanced chemical equation the mole ratios are:

1 : 3

0.0005 mol : x

Cross multiply these ratios

3 * 0.0005 = 1x

0.0015 = 1 x

x = 0.0015 mol

Now we will find out the mass of sodium bicarbonate

mass = moles * molar mass

mass of NaHCO₃ = 0.0015 mol * 84.007 g/mol

mass of NaHCO₃ = 0.126 g