Question

Convert 1300 ppm sodium chloride salt concentration into meq/l

• A. 22.22
• B. 20.22
• C. 18.75
• D. 23.25

Hint:

Divide the ppm value by the equivalent weight of sodium chloride, which comes from its molecular weight and its valence of one.

Answer 1

The Correct Option is A

Step 1: To convert a concentration from ppm (the same as mg per litre for a dilute water solution) into meq per litre, divide the ppm value by the equivalent weight of the salt.

\[\text{meq/l} = \frac{\text{ppm}}{\text{equivalent weight}}\]

Step 2: Find the equivalent weight of sodium chloride, NaCl. Its molecular weight is the atomic weight of sodium plus the atomic weight of chlorine: 23 + 35.5 = 58.5 g/mol. Since both Na+ and Cl- carry a single positive or negative charge (valence 1), the equivalent weight of NaCl is the same as its molecular weight, 58.5.

Step 3: Divide the given concentration by this equivalent weight: 1300 / 58.5 = 22.22 (rounded to two decimal places).

Step 4: So 1300 ppm of sodium chloride equals about 22.22 meq/l, which is option 1. The other values would only appear if a wrong equivalent weight were used, for example dividing by something close to 65 gives roughly 20, dividing by around 69 gives roughly 18.8, and neither matches the correct equivalent weight of NaCl.