Question

What is the molarity in 850 ml of solution containing 63 grams of Sodium Hydroxide?

Answer 1

Answer: 1.85M

Explanation:

Sodium hydroxide has a chemical formula of NaOH

Given that,

Amount of moles of NaOH (n) = ?

Mass of NaOH in grams = 63g

For molar mass of NaOH, use the molar masses:

Sodium, Na = 23g;

Oxygen, O = 16g;

Hydrogen, H = 1g

NaOH = (23g + 16g + 1g)

= 40g/mol

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

n = 63g / 40.0g/mol

n = 1.575 mole

Volume of NaOH solution (v) = 850mL

[Convert 850mL to liters

If 1000mL = 1L

850mL = 850/1000 = 0.85L]

Concentration of NaOH solution (c) = ?

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

c = n / v

c = 1.575 mole / 0.85L

c = 1.85M [1.85M is the concentration in moles per litres which is also known as molarity]

Thus, the molarity of the solution is 1.85M