Question

Calculate the volume Sodium Chloride solution required from stock solution of 75% to prepare the solution of 20% in 50 ml.​

Answer 1

Answer:

NaCl] : 9% (w/v)

Volume of solution : 50 mL

Mass of NaCl : ….. grams ?

You have to understand the concept of the concentration of % (w/v).

% (w/v) means X grams of solute in 100 mL of solution.

So, 9% (w/v) NaCl means 9 grams of NaCl in 100 mL of solution.

In 100 mL of solution, you need 9 grams of NaCl. How about in 50 mL ? By using this trick math. You are going to find out how much grams of NaCl

9 grams → 100 mL

X grams → 50 mL

X grams . 100 mL : 9 grams . 50 mL

X : (100 mL . 9 grams) / 50 mL

X : 18 grams.

So, if you want to make up 9% (w/v) of NaCl in 50 mL solution. You need 18 grams of NaCl.

I hope it will help you.

Explanation:

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