Question

What do you understand by ppm?
A. Parts per million
B. Particles per million
C. parts and particles per million
D. None of the above

Answer 1

Hint : This is a means of indicating very low chemical concentrations. Parts per million, or ppm, signifies out of a million, just as per cent means out of a hundred. Usually refers to a substance's concentration in water or soil.

Complete Step By Step Answer:
Parts per million (ppm) is an acronym that can alternatively be represented as milligrams per litre $\left( {mg \cdot {L^{ - 1}}} \right)$ . The mass of a chemical or contaminant per unit volume of water is the unit of measurement. The absolute fractional amount multiplied by one million equals one ppm.
So, the correct option is: (A) Parts per million.

Additional Information:
Importance of ppm measurement:-
The amount of minerals and gases dissolved in water is measured in parts per million (ppm) in water treatment. To transfer heat, we employ water as a medium. These dissolved contaminants in ppm can cause difficulties in the equipment, such as mineral scale and corrosion, as the water transmits heat. Water can only dissolve a certain number of parts per million of a mineral, depending on its properties. These minerals may then seek to come out of solution as the temperature and concentration of the water changes. To assist prevent these issues, we use treatment chemicals that are measured and added in ppm.

Note :
PPM is calculated or quantified using chemical tests. It can be determined using titration, colorimetric, or ion-selective-electrode (ISE) procedures to evaluate the water. The following equation is used to determine ppm in US English units: $ppm = \dfrac{{120,000\,\left( {lbs\,added} \right)}}{{Volume\,in\,gallons}}$