Step-by-step explanation:
1) When copper strip is immersed in dilute nitric acid it gives copper (II) nitrate ,water and nitrogen mono-oxide.
The balanced equation for the reaction between copper immersed in dilute nitric acid.

2) The pH of the solution was initially acidic and as the reaction proceeds the pH of the solution increases. At the end of the reaction solution becomes neutral. And the neutral solution has pH value of 7.