Question 1024455
We use the definition of logarithms for A and B
:
A) 7.4 = -log (base 10) H+
note multiply both sides of = by -
-7.4 = log (base 10) H+
H+ = 10^-(7.4)
H+ = 0.00000004 moles per liter
:
B) 2 = -log (base 10) H+
-2 = log (base 10) H+
H+ = 10^-2
H+ =  0.01 moles per liter
: