Question

Concentrated aqueous sulphuric acid is 98% H2SO4 by mass & has a density of 1.80gm/L. Volume of acid required to make one litre of 0.1M H2SO4 solution is??

(answer is 5.55 mL. Plz explain how to solve it)

Answer 1

Density = M/V
=> 1.80 g/ml = 9.8g/volume
=> Volume = 9.8/1.80 = 5.44 ml

5.44 ml will be required to make a 100% H2SO4
But since 98% H2SO4 is required

So,volume required = 100*5.44/98
                                =5.55 ml

Answer 2

Answer: 0.0055 L

Solution :

98 % $H_2SO_4$ solution means 98 g of $H_2SO_4$ is present in 100 g of solution.

Mass of solution = 100 g

Density of solution =  1.80 g/ml

Now we have to calculate the volume of solution.

$Volume=\frac{Mass}{Density}=\frac{100g}{1.80g/ml}=55.55ml$  

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 $H_2SO_4$=$\frac{\text {given mass}}{\text {molar mass}}=\frac{98}{98}=1 mole$

$V_s$ = volume of solution in ml

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

$Molarity=\frac{1moles\times 1000}{55.55}=18mole/L$

Therefore, the molarity of solution will be 18 mole/L

Now using molarity equation:

$M_1V_1=M_2V_2$

$18M\times V_1=0.1M\times 1L$

$V_1=0.0055L$