# What is the hydrogen ion concentration in a urine specimen that registers a pH of 4 on a strip of pH paper?

##### 1 Answer

Well,

#### Explanation:

And I didn't even need a calculator.........

By definition,

And if

And we know that hydroxide/hydronium ions obey the following equilibrium in aqueous solution.......

Why do we use such an absurd definition? Well, back in the day, approx. 30-40 years ago BEFORE the proliferation of hand-held electronic calculators, students and engineers would routinely use log tables for lengthy calculation involving multiplication and division. because the product

These days with a simple electronic calculator (and I bought one for a quid in a discounter's shop a couple of weeks ago) we have access to a computational power that would have astonished both Newton and Gauss (they say that Gauss in particular, a mathematical prodigy, had memorized the log tables so that he could do his calculations).