Answer:
Explanation:
pH is a measure of the concentration of H₃O⁺ ions in a solution.
It is defined as:
[tex]pH=\log \dfrac{1}{[H_3O^+]}=-\log [H_3O^+][/tex]
For the given substances
Sustance [H₃O⁺] pH = - log [H₃O⁺]
M
A 4×10⁻⁶ -log (4×10⁻⁶) = 5.4 ← answer
B 6×10⁻⁷ -log (6×10⁻⁷) = 6.2
C error - - - - - -
D 1.3×10⁻¹ -log (1.3×10⁻¹) = 0.89
Thus, the unknown substace most likely is A.