SiF4 or BF3 to symmetrical h...toh unki dipole zero ....or XeF4 me dipoles ki direction dekhna wo ek dusre ke effect ko cancel kr deti h....or dipole ki direction lone pair ki taraf hoti h....

Polar Molecules:

A polar molecule is a molecule in which the distribution of electrons between the covalently bonded atoms is not even. This uneven distribution of electrons causes a permanent dipole moment, which makes the molecule polar. A polar molecule has a positive and negative end, or pole, due to the uneven distribution of electrons.

Options:

a. SiF4: Silicon Tetrafluoride (SiF4) is a non-polar molecule because it has a symmetric tetrahedral shape, and the electronegativity difference between silicon (1.90) and fluorine (3.98) is not significant enough to create a dipole moment.

b. XeF4: Xenon Tetrafluoride (XeF4) is a non-polar molecule because it has a symmetric square planar shape, and the electronegativity difference between xenon (2.6) and fluorine (3.98) is not significant enough to create a dipole moment.

c. BF3: Boron Trifluoride (BF3) is a non-polar molecule because it has a trigonal planar shape, and the electronegativity difference between boron (2.04) and fluorine (3.98) is not significant enough to create a dipole moment.

d. SF4: Sulfur Tetrafluoride (SF4) is a polar molecule because it has a trigonal bipyramidal shape, and the electronegativity difference between sulfur (2.58) and fluorine (3.98) creates a dipole moment. The lone pair of electrons on the sulfur atom also contributes to the polarity of the molecule.

Conclusion:

In conclusion, the polar molecule is SF4, while the other molecules are non-polar. The shape and electronegativity difference between the atoms in a molecule determine whether the molecule is polar or non-polar.