# Which of the following have zero dipole moment ? $(i)\; H_2;\; (ii)\;HF;\; (iii)\; CH_4; \; (iv) CHCl_3$

$(a)\;(i)\; and\;(iii) \\ (b) \; (ii)\;and \;(iii) \\ (c) \;(i)\;and \;(iv) \\ (d)\;(ii)\;and (iv)$

Homonuclear species as well as a species where central atom is attached to same atom has zero dipole moment.
Hence a is the correct answer.