The \( \mathrm{pH} \) of a solution obtained by mixing \( 5 \, \text{mL} \) of \( 0.1 \, \text{M} \, \text{NH}_4\text{OH} \) solution with \( 250 \, \text{mL} \) of \( 0.1 \, \text{M} \, \text{NH}_4\text{Cl} \) solution is ________ \( \times 10^{-2} \). (Nearest integer)
Given: \( \mathrm{p}K_b(\text{NH}_4\text{OH}) = 4.74 \)
