\( x \) \( \text{mg} \) of pure \( \mathrm{HCl} \) was used to make an aqueous solution. \( 25.0 \, \text{mL} \) of \( 0.1 \, \text{M} \) \( \mathrm{Ba(OH)_2} \) solution is used when the \( \mathrm{HCl} \) solution was titrated against it. The numerical value of \( x \) is _______ \( \times 10^{-1} \). (Nearest integer) [Given: Molar mass of \( \mathrm{HCl} \) and \( \mathrm{Ba(OH)_2} \) are \( 36.5 \) and \( 171.0 \, \text{g mol}^{-1} \) respectively]