Question

What is the molarity of the solution produced when 145 g NaCl is dissolved in sufficient water to prepare 2.75 L of solution? *

Answer 1

Answer: Option D) 0.902M

Explanation:

Sodium chloride has a chemical formula of NaCl

Given that,

Amount of moles of NaCl (n) = ?

Mass of NaCl in grams = 145g

For molar mass of NaCl, use the molar masses:

Sodium, Na = 23g;

Chlorine,Cl = 35.5g

NaOH = (23g + 35.5g)

= 58.5g/mol

Since, amount of moles = mass in grams / molar mass

n = 145g / 58.5g/mol

n = 2.48 mole

Amount of moles of NaCl (n) = 2.48 mole

Volume of NaCl solution (v) = 2.75L

Concentration of NaCl solution (c) = ?

Since concentration (c) is obtained by dividing the amount of solute dissolved by the volume of solvent, hence

c = n / v

c = 2.48 mole / 2.75L

c = 0.9018M

Approximately, c = 0.902M

[c is the concentration in moles per litres which is also known as molarity]

Thus, the molarity of the solution is 0.902M