Question

Aqueous hydrochloric acid HCl reacts with solid sodium hydroxide NaOH to produce aqueous sodium chloride NaCl and liquid water H2O . What is the theoretical yield of water formed from the reaction of 36.1g of hydrochloric acid and 49.9g of sodium hydroxide? Be sure your answer has the correct number of significant digits in it.

Answer 1

The reaction between hydrochloric acid and NaOH is,

HCl(aq) + NaOH(aq) NaCl(aq) + H₂O(l)

Also given,

Mass of HCl = 36.1 g

Mass of NaOH = 49.9 g

Calculating the number of moles of HCl and NaOH,

= 36.1 g of HCl x (1 mol /36.46 g)

= 0.9901 mol of HCl

Similarly,

= 49.9 g of NaOH x ( 1 mol /40 g)

= 1.2475 mol of NaOH

Now, using the calculated moles of each reactant and the mole ratio from the balanced chemical reaction to calculate the number of moles of water formed.

= 0.9901 mol HCl x ( 1 mol of H₂O / 1 mol of HCl)

= 0.9901 mol of H₂O

Similarly,

= 1.2475 mol of NaOH x ( 1 mol of H₂O / 1 mol of NaOH)

= 1.2475 mol of H₂O

Now, the number of moles of H₂O formed from the given moles of HCl is less than the number of moles of H₂O formed from the given moles of NaOH.

Thus, HCl is limiting reactant.

Now, The number of moles of H₂O formed from the given moles of limiting reactant is called theoretical yield.

Thus,

The theoretical yield of water = 0.9901 mol

Converting this number of moles to grams,

= 0.9901 mol x ( 18.02 g / 1 mol)

= 17.8 g of number H₂O