The density of a 0.75M NaOH solution is 1.1g/ml. Calculate the mass percent of NaOH in the solution

2.73%

Explanation:

Molarity of NaOH = 0.75 M

Density of solution = 1.1 g/mL

Mass percent of NaOH = ?

Solution:

Number of moles of NaOH = 0.75 mol    from 0.75 mol/L

Mass of NaOH = number of moles × molar mass

Mass of NaOH = 0.75 mol × 40 g/mol

Mass of NaOH =  30 g

Mass of solution:

d = m/v

1.1 g/ mL = m/ 1000 mL

m = 1100 g

Percentage of NaOH:

% NaOH = mass of solute / mass of solution × 100

% NaOH =  30 g/ 1100 g × 100

% NaOH = 2.73%