Calculate the mass of sodium hydroxide that will be required to neutralize 250 g of a solution

Calculate the mass of sodium hydroxide that will be required to neutralize 250 g of a solution with a mass fraction of hydrogen chloride of 20%.

Given:

m (HCl) = 250 g

w% (HCl) = 20%

Find:

m (NaOH) -?

Solution:

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

1) Find the mass of hydrogen chloride in the reacted solution:

m (HCl) = 250 g * 0.2 = 50 g

2) Find the amount of hydrogen chloride:

n (HCl) = m: M = 50 g: 36.5 g / mol = 1.37 mol

3) We compose a logical expression:

If 1 mole of HCl requires 1 mole of NaOH,

then 1.37 mol HCl will require x mol NaOH,

then x = 1.37 mol.

4) Find the mass of alkali required for the reaction to proceed:

m (NaOH) = n * M = 1.37 mol * 40 g / mol = 54.8 g.

Answer: m (NaOH) = 54.8 g.