How can u directly compare the number of drops needed for permanent suds when u use a different volume of h2o?

Question

For testing the water from the ion-exchange resin, you used 1 to 3 ml of water, instead of 5mL of water. How can you directly compare the number of drops needed for permanent suds when you use a different volume of water?

Answer 1

Just use a proportion. If you are trying to get permanent suds in 5 mL of water, take the number of drops required in 3 mL of water and multiply by 5/3, or the number in 1 mL and multiply by 5.