Ionic Equilibrium

The dissociation constant of acetic acid is \(x\times10^{-5}\). When 25 mL of 0.2 \(\mathrm{M~CH_3COONa}\) solution is mixed with 25 mL of 0.02 \(\mathrm{M~CH_3COOH}\) solution, the pH of the resultant solution is found to be equal to 5. The value of \(x\) is ____________