Question

Which boiling point is lower an why?

Answer 1

Answer:

4.

Explanation:

Is expected because of the stronger dipole forces in SiH4.

Answer 2

Answer:4

Explanation:

If we carefully observe the electronegativity of the elements in question

P-2.19

N-3.04

C-2.55

Si-1.9

H-2.2

SiH4 is definitely more polar than CH4 hence greater dipole forces of a higher boiling point. NH3 is more polar than PH3 hence NH3 has greater dipole forces and a higher boiling point. Electronegative differences influences the polarity of a bond. The greater the electro negativity difference between bonding atoms, the greater the dipole forces and the greater the boiling point.