Question

the concentration of a proper chlorine - and - water sanitizing solution is: 50 ppm 100 ppm 200 ppm 400 ppm

Explanation:

According to general guidelines for chlorine - and - water sanitizing solutions, a concentration of 50 ppm is a common and proper value for many sanitizing applications. Higher concentrations like 100 ppm, 200 ppm, and 400 ppm may be too strong for regular sanitizing (except in some very specific, heavy - duty, and carefully monitored situations which are not the 'proper' general case).

Answer:

50 ppm