Number of molecules which are ready to act as Arrhenius base in the above substances are ______

$\mathrm{HCl},{\mathrm{BF}}_3,{\mathrm{AlCl}}_3,{\mathrm{NH}}_3,\mathrm{NaOH},\mathrm{Ca}{\left(\mathrm{OH}\right)}_2,{\mathrm{H}}_2{\mathrm{SO}}_4,{\mathrm{SnCl}}_4,{\mathrm{Co}}^{+2},{\mathrm{Ag}}^{+}$