Question

The molarity of 20%(W/W) solution of sulfuric acid is 2.55 M.
The density of the solution is:
(1) 1.25 g cm
(2) 0.125 g 1
(3) 2.55 g cm
(4) unpredictable​

Answer 1

Given:

Mass % = 20 %

Molarity = 2.55 M

To Find:

Density (d) of Sulphuric acid.

Calculation:

- The molecular weight of sulphuric acid is 98 gm.

- We have a formula for calculating molarity by mass % as follows:

M = (10 × d × wt %)/ M.wt

⇒ d = (M × M.wt) /(10 × wt %)

⇒ d = (2.55 × 98) /(10 × 20)

⇒ d = 1.25 g/cm³

- So the density of the solution is:  (1) 1.25 gm/ cm³.