Sodium hydroxide was added to 100 g of a 25% hydrochloric acid solution

Sodium hydroxide was added to 100 g of a 25% hydrochloric acid solution, calculate the mass of the formed salt and the mass of sodium hydroxide reacted.

Given:

m (HCl) = 100 g

w% (HCl) = 25%

To find:

m (NaCl) -?

m (NaOH) -?

Decision:

NaOH + HCl = NaCl + H2O, – we solve the problem based on the composed reaction equation:

1) Find the mass of hydrochloric acid in the solution:

m (HCl) = 100 g * 0.25 = 25 g

2) Find the amount of acid:

n (HCl) = m: M = 25 g: 36.5 g / mol = 0.68 mol

3) Find the mass of salt by the first logical expression:

if 1 mol of HCl gives 1 mol of NaCl,

then 0.68 mol HCl will give x mol NaCl,

then x = 0.68 mol.

m (NaCl) = n * M = 0.68 mol * 58.5 g / mol = 39.78 g

4) Find the mass of sodium hydroxide by the second logical expression:

if 1 mol of NaOH gives 1 mol of NaCl,

then x mole of NaOH will give 0.68 mole of NaCl,

then x = 0.68 mol

m (NaOH) = n * M = 0.68 mol * 40 g / mol = 27.2 g.

Answer: m (NaCl) = 39.78 g; m (NaOH) = 27.2 g.