Question

State true or false
ppm is equal to 1 mg per kg
A.True
B.False

Answer 1

To solve this question, we need to first understand the definitions and meanings of the terms given to use. Since both these units are used for measuring the concentration, if possible, we need to establish a mathematical relation between them to get the final answer.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Ppm stands for parts per million. Now you may be wondering what this term means. It is nothing but a measure of concentration of a solute in a given solution. It helps in visualizing how many parts of the solute are present per million (or 1,000,000) parts of the solvent.
Now, 1 mg per kg is a measure of concentration by using weight as the deciding factor. To create a unified weight measure for this unit, we can convert the kg to mg. 1 kg can be calculated to be equal to ${10^6}$ mg. Hence, we can say that in 1 mg per kg, there is 1 mg of the solute present per ${10^6}$ mg of the solvent. ${10^6}$ is equal to 1 million. Hence, in this unit, 1mg of solute is present per million mg of solvent.
Hence, both these units have a solute to solvent ratio of $1:{10^6}$.
Hence, we can say that 1 ppm is equal to 1 mg per kg is a TRUE statement.

Hence, Option A is the correct option.

Note: Ppm is used for solutions which have extremely low concentrations of the solute. Such a solution would be very dilute in nature and would have a density which is almost equivalent to the density of the solvent. Hence, 1 ppm can be translated as 1 part of the solute is present per 1 million parts of the solvent.