Q.Drooping and Discoloured Brussells Sprouts Plants
I have recently planted sprout plants, and although at least 3 have seemed to have taken quite well, 6 have wilted and died after the first three leaves went a purple colour and drooped. I believe that my soil is acidic. Could this be the problem, and if so, what can I do to resolve this issue, and why have the other plants not died? Thanks in anticipation.

Certified GKH Gardening Expert
It does sounds like a nutrient issue, but not so much acidic soil by itself. Vegetables actually do ok in somewhat acidic soil.
Purple color in the plants indicates a phosphorus deficiency, which can be made worse by acidic soil or cold weather. A severe deficiency could kill the plants. This article will help: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm
This article will help with lowing the acid:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/lower-acid-soil.htm