Question

Concentrated H2SO4 (sulfuric acid) is 97% by mass and has a density of 1.84g/mL. What is its molarity?

Answer 1

Let volume of solution be 1 L

volume , V = 1 L = 1*10^3 mL

density, d = 1.84 g/mL

we have below equation to be used:

mass = density * volume

= 1.84 g/mL *1*10^3 mL

= 1840.0 g

This is mass of solution

mass of H2SO4 = 97.0 % of mass of solution

= 97.0*1840.0/100

= 1784.8 g

Molar mass of H2SO4 = 2*MM(H) + 1*MM(S) + 4*MM(O)

= 2*1.008 + 1*32.07 + 4*16.0

= 98.086 g/mol

mass(H2SO4)= 1784.8 g

we have below equation to be used:

number of mol of H2SO4,

n = mass of H2SO4/molar mass of H2SO4

=(1784.8 g)/(98.086 g/mol)

= 18.2 mol

volume , V = 1 L

we have below equation to be used:

Molarity,

M = number of mol / volume in L

= 18.2/1

= 18.2 M

Answer: 18.2 M