Dissolve 0.5gm of mannitol in 5 ml of solvent

Explanation = 0.5g x 20=10 gm

5 ml x 20=100 ml

10 gm in 100 ml means 10% solution

10% (w/v) = 10 g/100 mL

10 g / 100 mL* 5 mL = 0.5 g

Weigh 0.5g of mannitol and dissolve in 5 mL of solvent/solution.

10% mannitol solution mean 100l contain 10gm mannitol.

So,

1ml solution contain = 10/100 = 0.1 gm mannitol.

5ml solution contain = 0.1×5 = 0.5 gm mannitol

Add 80ml water into a beaker.

then add 10gm mannitol into the water.

stir until the solution is clear.

make up the volume to 100ml.

(you may need to warm up the water in order to dissolve the mannitol easily.)

stoichiometrically 10% Mannitol means 10 g in 100 mL (0.1 g / mL)

From the above stock take 5 ml.