You have 350 mL of a 5 M NaCl solution. You are told to use this to prepare 500

ID: 985011 • Letter: Y

Question

You have 350 mL of a 5 M NaCl solution. You are told to use this to prepare 500 mL of a 1 M NaCl solution. The molecular weight of NaCl is 58.4 g.

A. Pour 225 mL of the 5 M NaCl into a 500 mL graduated cylinder and add distilled water to 500 mL.

B. Pour 100 mL of the 5 M NaCl into a 500 mL graduated cylinder and add distilled water to 500 mL.

C. Pour 50 mL of the 5 M NaCl into a 500 mL graduated cylinder and add distilled water to 500 mL.

D. Pour 300 mL of the 5 M NaCl into a 500 mL graduated cylinder and add distilled water to 500 mL.

Since you have to prepare 1 M NaCl solution from 5 M NaCl solution

Therefore, let the volume of 5M NaCl required be 'x' ml

Thus, moles of NaCl in 5 M solution = molarity*volume of solution in litres = 0.005*x

Now, Moles of NaCl present in 1 M NaCl solution = 1*0.5 = 0.5

As both x ml of 5 M solution and 500 ml of 1 M solution contains equal moles of NaCl

Therefore, 0.005*x = 0.5

o, x = 100 ml

Hence, the correct option is :- (B)

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