Answer:
The name of the cation
Explanation:
The name of a binary ionic compound is
name_of_cation name_of_anion
Thus, the first part of the name is the name of the cation.
For example, the first part of the name of Na⁺Cl⁻ is sodium.
The pH is calculated using the expression: pH = - log [H3O+].
To find the concentration of [H3O+]
[H3O+] = 10^(-pH)
Solving the RHS we have 10^(-4.240) = 0.1440
Hence the concentration of H3O+ is 0.1440.