Question

What is the concentration of a stock solution if 20 mL was used to make 400 mL of a 1.44

M solution?
30 M
40 M
50 M
5M

Answer 1

Given :

Volume of stock solution,
`V_s = 20\ mL`.

Volume of diluted solution,
`V_d = 400 \ mL`.

Molarity of diluted solution,
`M_d = 1.44\ M`.

To Find :

The concentration of the stock solution.

Solution :

We know, dilution factor is given by :

`D.F=\frac{V_ {diluted}}{V_(stock)}` ....1)

and
`D.F= (M_(stock))/(M_(diluted))` ....2)

Putting volume in above equation, we get :

D.F = 400/20

D.F = 20

Putting value of D.F in equation 2) we get :

`(M_(stock))/(M_(diluted)) = 20\\\\M_(stock) = 20* 1.44\\\\M_(stock) =28.8\ M`

The concentration of stock solution is nearest to 30 M.

Therefore, the correct option is 1) 30 M.