I believe the pH is 7. If you would like me to explain comment.
i just learnt this recently but i need to look through my notes again.
I would say soil would be your best option. This is because out of all these, soil collects a lot of different substances and could have easily absorbed something that then killed the organism.
Explanation:
2KNO3 + BaCl2 = Ba(NO3)2 + 2KCl
I actually tried. I'd this is wrong , can you please inform me? thank you