Question

To prepare a 50 PPM chlorine based sanitizing solution, what is the correct ratio of chlorine to water?

1) 1:100
2) 1:500
3) 1:1000
4) 1:2000

Answer 1

To prepare a 50 PPM chlorine solution, the ratio of chlorine to water is 1:20000, meaning 1 gram of chlorine should be mixed with 20,000 grams (20 liters) of water.

Step-by-step explanation:

To create a 50 PPM (parts per million) chlorine based sanitizing solution, we need to determine the ratio of chlorine to water that will yield this concentration. One ppm is equivalent to 1 milligram of a substance in 1 liter of water. Therefore, a 50 ppm chlorine solution would mean there are 50 milligrams of chlorine in each liter of water.

To find the correct ratio, you can use the unitary method. For instance:

1. To achieve 1 ppm, you would mix 1 milligram of chlorine with 1 liter of water, for a ratio of 1:1,000,000.
2. So, for 50 ppm, you would mix 50 milligrams of chlorine with 1 liter of water.
3. Given that 1 liter of water is equivalent to 1,000 grams (since the density of water is roughly 1 g/mL), this ratio can be simplified to 50 milligrams of chlorine to 1,000 grams of water.

By converting the milligrams to grams (since there are 1,000 milligrams in a gram), the 50 milligrams becomes 0.05 grams. Hence, the ratio of chlorine to water in grams is 0.05:1000. To translate this into a more manageable solution ratio, it can be divided further:

0.05 g of chlorine per 1000 g of water is the same as 1 g of chlorine per 20,000 g of water. Thus, the correct ratio of chlorine to water for a 50 PPM solution would be 1:20000 (Option 4).