Add 500 L solvent.

STEP-I:

Find the vol. of 1 g of Lenoleneic Acid by using the formula; V=m/d

mass = 25g

d = 0.902 g/mL

Volume (V) =?

V=25/0.902 = 1.1 mL

STEP-II:

Firstly prepare 1000 mg/L (ppm) Lenoleneic Acid as stock solution.

For stock solution dissolve 1g i.e. 1.1mL Lenoleneic Acid in 1000 mL solvent; it will be 1000 mg/L or 1000ppm stock solution. To save chemicals, you can dissolve 0.1g or 0.11mL Lenoleneic acid in 100 mL solvent, it will also be 1000 mg/L solution.

STEP-III:

Now apply dilution formula to get required volume of 50 mg/L solution. Let,s suppose you need 100 mL of 50 mg/L working solution. You can prepare it by the following procedure:

Stock Required

M1V1 = M2V2

1000 mg/L x V1 = 50 mg/L x 100 mL

V1 = 5000/1000 = 5mL

It means you will take 5 mL from stock solution and add to 95 mL solvent. It will be 50mg/L solution of Lenoleneic Acid.

Thanks all for your kind response. And special thanks to Aslam Mirza.