C++ Variable meaningful name

#include <iostream>
#include <cmath>
using namespace std;
int main()/*from   w w  w  .j ava 2 s .  com*/
{
   double hydron, pHlevel;
   cout << "Enter the hydronium ion concentration: ";
   cin  >> hydron;
   pHlevel = -log10(hydron);
   cout << "The pH level is " << pHlevel << endl;
   return 0;
}