Answer: pH of the solution is 5.47
Step-by-step explanation: Since HNO3 is a strong acid the concentration of H+ is the same as NO3- only because they are in 1-to-1 ratio. Both ions will have 3.4 x 10^-6 M.
The formula of pH is: pH = -log( the equilibrium concentration of H+ )
When you plug in the concentration of H+:
pH = -log (3.4 x 10^.6 M)
pH = 5.47
Remember: Only the digits after the decimal point are significant figures in logarithms.
For example: 5.47 only has 2 significant figures.