Hello!
To determine [H₃O⁺], we need to apply the Henderson-Hasselback equation, since this is a case of an acid and its conjugate base:
![pH=pKa+log( \frac{[A^{-}] }{[HA]} )](https://tex.z-dn.net/?f=pH%3DpKa%2Blog%28%20%5Cfrac%7B%5BA%5E%7B-%7D%5D%20%7D%7B%5BHA%5D%7D%20%29)

Now, we use the definition of pH and clear [H₃O⁺] from there:
![pH=-log[H_3O^{+}]](https://tex.z-dn.net/?f=pH%3D-log%5BH_3O%5E%7B%2B%7D%5D%20)
![[H_3O^{+}] = 10^{-pH} =10^{-3,84}=0,00014 M](https://tex.z-dn.net/?f=%20%5BH_3O%5E%7B%2B%7D%5D%20%3D%2010%5E%7B-pH%7D%20%3D10%5E%7B-3%2C84%7D%3D0%2C00014%20M)
So, the [H₃O⁺] concentration is
0,00014 M
Have a nice day!
1. True 2. I think A and D. I’m not sure though
Answer:
(B) saprophytes
Explanation:
parasite-an organism that lives on or in a host organism and gets its food from or at the expense of its host.
symbiotic-an evolved interaction or close living relationship between organisms from different species, usually with benefits to one or both of the individuals involved
There are several different kinds of indicator electrodes. Several metals, such as silver, copper, lead, cadmium, and mercury, will participate in a reversible electron exchange and can serve as indicator electrodes for their ions.