Question

Calculate the mass of pure sodium chloride that will yield enough hydrogen chloride gas to neutralize 25cm³ of 0.5M potassium trioxocarbonate (V) solution 

Answer 1

$\textsf{no. of moles of } K_2CO_3 = c × V = \\ 0.5 × \dfrac{25}{1000} = 0.0125 \textsf{ moles}$

$2HCl + K_2CO_3 \to 2KCl + H_2CO_3$

from the reaction above, 2 moles of HCl reacts 1 mole of K₂CO₃.

This means that 0.025 moles of HCl reacts 0.0125 moles of K₂CO₃.

$2NaCl + H_2SO_4 \to NaSO_4 + 2HCl$

from the reaction above, 2 moles of NaCl produces 2 moles of HCl.

This means that 0.025 moles of NaCl reacts with 0.025 moles of H₂SO₄.

1 mole of NaCl is 58.5g

therefore, 0.25 moles of NaCl is 14.625g

therefore, 14.625g of NaCl will yield enough HCl to neutralize 25cm³ of 0.5M K₂CO₃.