Why is chloride measurment 0
Most likely this was an artificial &quot;lake&quot; sample and someone gave you distilled water instead. Making artificial water samples is not an unusual practice in teaching laboratories.
Natural water cannot have zero concentration of chloride ion. Sodium and chloride ions are very common contaminants even in pure reagents. There is no &quot;zero&quot; concentration concept in analytical chemistry at all. The proper practice is to write &quot;Not detected&quot; instead of saying 0 ppm. All it means that it was below the detection limit of the ion-selective electrode. Ion selective electrode usually measure samples in parts per million (mg/L) range. Typical limits of detections are in single digit ppm.