If \( 1 \, \text{mM} \) solution of ethylamine produces \( \text{pH} = 9 \), then the ionization constant (\( K_b \)) of ethylamine is \( 10^{-x} \). The value of \( x \) is __________ (nearest integer).[The degree of ionization of ethylamine can be neglected with respect to unity.]
