Question

Comercially available concentrated hydrochloric acid contains 45% HCl by mass. What is the molarity of this solution? The density is 1.19g/ml

Answer 1

Answer:

$\bigstar{\bold{Molarity=14.64\:M}}$

Explanation:

$\Large{\underline{\underline{\bf{Given:}}}}$

• % of HCl in the solution = 45%
• Density = 1.19 g/ml

$\Large{\underline{\underline{\bf{To\:Find:}}}}$

• Molarity of the solution

$\Large{\underline{\underline{\bf{Solution:}}}}$

→ Given that the % of HCl in the solution is 45%.

→ Hence

  The mass of HCl present is 45 g

→ Now we have to find the volume of the solution

→ Volume of the solution is given by

  Volume = Mass/Density

  Volume = 100/1.19

  Volume = 84 ml

→ Converting it to L we get

  Volume = 84/1000

  Volume = 0.084 L

→ Now we have to find the number of moles of solute

  Number of moles of solute = Given mass/Molar mass

  Number of moles of solute = 45/1 + 35.5

  Number of moles of solute = 1.23 moles

→ Now molarity is given by

  Molarity =  number of moles of solute/Volume of solution in L

  Molarity = 1.23/0.084

  Molarity = 14.64 M

→ Hence molarity of the solution is 14.64 M

$\boxed{\bold{Molarity=14.64\:M}}$

$\Large{\underline{\underline{\bf{Notes:}}}}$

→ Molarity is given by

  Molarity = number of moles of solute/Volume of solution in L

→ Molality is given by

  Molality = number of moles of solute/ Mass of solvent in kg