Question

What will be the molarity of 0.1 molal h2so4 solution having density 1.2 g/ml?

Answer 1

Answer : The molarity of solution will be, 0.118 mole/L

Solution : Given,

Molar mass of $H_2SO_4$ = 98 g/mole

0.1 molal $H_2SO_4$ solution means 0.1 moles of $H_2SO_4$ present in 1000 g of water.

Mass of water (solvent) = 1000 g

Mass of $H_2SO_4$(solute) = $0.1moles\times 98g/mole=9.8g$

Mass of solution = Mass of solute + Mass of solvent = 1000 + 9.8 = 1009.8 g

Now we have to calculate the volume of solution.

$Volume=\frac{Mass}{Density}=\frac{1009.8g}{1.2g/ml}=841.5ml$

Molarity : It is defined as the number of moles of solute present in one liter of solution.

Formula used :

$Molarity=\frac{n\times 1000}{V_s}$

where,

n = moles of solute $H_2SO_4$ = 0.1 moles

$V_s$ = volume of solution in liter

Now put all the given values in the formula of molarity, we get

$Molarity=\frac{0.1moles\times 1000}{841.5L}=0.118mole/L$

Therefore, the molarity of solution will be, 0.118 mole/L