Question

The concentration (M) of HCl in a solution prepared by dissolving 5.5 g of HCl in 200 g of C2H6O is __________ M. The density of the solution is 0.79 g/mL.

Answer 1

Volume = mass/density

= 200/0.79

= 253 ml.

Moles = 5.5/36.5 = 0.15

So,

Molarity = moles/volume in litre

= 0.15/253×1000

= 0.59 M

Answer 2

Answer: The concentration of HCl in solution is 0.58 M

Explanation:

We are given:

Mass of HCl (solute) = 5.5 g

Mass of ethanol (solvent) = 200 g

To calculate volume of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of solution = 0.79 g/mL

Mass of solution = 5.5 + 200 = 205.5 g

Putting values in above equation, we get:

$0.79g/mL=\frac{205.5g}{\text{Volume of solution}}\\\\\text{Volume of solution}=\frac{205.5g}{0.79g/mL}=260.13mL$

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}$

We are given:

Given mass of HCl = 5.5 g

Molar mass of HCl = 36.5 g/mol

Volume of solution = 260.13 mL

Putting values in above equation, we get:

$\text{Molarity of solution}=\frac{5.5\times 1000}{36.5\times 260.13}=0.58M$

Hence, the concentration of HCl in solution is 0.58 M