Question

A solution which has [ H3O+] = 8.7 × 10-7 M is A) acidic B) basic C) neutral

Answer 1

We need to calculate the pH of H3O+ to know if the solution is acidic, basic or neutral.

$pH=-log_{10}\lbrack H_3O^+\rbrack$

pH = -log10 [8.7x10^-7]

pH =6.06

The pH is acidic because it is less than 7.