Which of the following relations is correct for a basic aqueous solution?

Write true or false for the following statement:
On the $pH$ scale,we can measure $pH$ from $0$ (very acidic) to $14$ (very alkaline).

Which statement is incorrect?

You have two solutions $A$ and $B$. The $pH$ of solution $A$ is $6$ and the $pH$ of solution $B$ is $8$. Which solution has more hydrogen ion concentration? Which one of these is acidic and which one is basic?

If the concentration of hydronium ions in an aqueous solution is $[H_3O^+] = 10^{-5} \; M$,what is the $pOH$ of the solution?

The $pH$ of a water sample collected from a river was found to be acidic in the range of $3.5 - 4.5$. On the banks of the river were several factories that were discharging effluents into the river. The effluents of which one of the following factories is the most likely cause for lowering the $pH$ of river water?