Question

What is the correct unit for the following solution?
 $ 0.5mg $ of arsenic dissolved in $ 1kg $ of solution. (All the symbols given are in their standard form).
(A) $ w/w $
(B) m
(C) M
(D) $ v/v $
(E) ppm

Answer 1

Hint: We know that in an aqueous solution, two parts exist, namely solute and solvent. They are the two basic solution concentration terms that you need to know. We always need to keep an account of the amount of solute in the solution. The amount of solute in the solvent is what is called the concentration of a solution.

Complete answer:
The concentration of solution which describes the composition of the solution either qualitatively or quantitatively. To describe the concentration of solution quantitatively more methods are available. There are mass percentages, volume percentage, ppm, mole fraction, normality, molarity, and molality. One well known application of density is determining whether an object will float on water or not. The floating of ships and diving of submarines are due to their density difference. When a solution has more solute in it, we call it a concentrated solution. Whereas when the solution has more solvent in it, we call it a dilute solution. Now that you understand the concept of what concentration is, let's move on to the different methods of expressing concentration. $ w/w\text{ }% $ of a solute in a solution can be calculated by dividing the $ % $ of solute multiplied with the mass of that solute in the solution, by the total mass of all solutes in the solution.
Therefore, the correct answer is option A.

Note:
Remember that In general, liquids are less dense solids and gases are less dense than liquids. This is due to the fact that solids have densely packed particles whereas liquids are materials where particles can slide around one another and gases have particles that are free to move all over the plane.