Number of compounds from the following with zero dipole moment is \( \_ \_ \_ \_ \_ \).
\( \mathrm{HF}, \mathrm{H_2}, \mathrm{H_2S}, \mathrm{CO_2}, \mathrm{NH_3}, \mathrm{BF_3}, \mathrm{CH_4}, \mathrm{CHCl_3}, \mathrm{SiF_4}, \mathrm{H_2O}, \mathrm{BeF_2} \)