A2.900×10−2 m solution of nacl in water is at 20.0∘
c. the sample was created by dissolving a sample of nacl in water and then bringing the volume up to 1.000 l. it was determined that the volume of water needed to do this was 999.2 ml . the density of water at 20.0∘c is 0.9982 g/ml.

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The question should be "What is the mole fraction of salt in this solution?"

Below are the choices:

(A) 5.23 x 10-4 
(B) 99.95 x 10-2 
(C) 5.23 x 10-2 
(D) 99.95 x 10-4

The answer is A) 5.23 x 10-4