Answer:
The answer to your question is below
Explanation:
pH definition
 pH = - log [H⁺]
a) For pH = 2.4, solution A
 2.4 = -log[H⁺]
 [H⁺] = antilog⁻².⁴
 [H⁺] = 0.00398
 For pH = 9.4, solution B
 [H⁺] = antilog⁻⁹.⁴
 [H⁺] = 3.98 x 10⁻¹⁰
b) Divide hydrogen-ion concentration of solution A by hydrogen-ion concentration of solution B.
 0.00398 / 3.98 x 10⁻¹⁰
 10000000 times
c) By 7, because 7 is the number of zeros