Answer
a)
$10^{-3.2}\approx6.30957\cdot10^{-4}~M$
$10^{-2.9}\approx1.25893\cdot10^{-3}~M$
b) California wine
Work Step by Step
We know that pH is given by the formula:
$pH=-\log[H^+]$
Thus
$H^+=10^{-pH}$.
a) Hence, here the hydrogen ion concentrations are:
$10^{-3.2}\approx6.30957\cdot10^{-4}~M$
and
$10^{-2.9}\approx1.25893\cdot10^{-3}~M$
b) Thus the California wine has a lower hydrogen ion concentration.