WHY DOES NH3 FORMS HYDROGEN BOND BUT PH3 DOES NOT?

Asked by Jinu sony | 9th Oct, 2013, 06:07: PM

Expert Answer:

The stability of hydrides decrease down the group due to decrease in bond dissociation energy down the group.

  NH3 > PH3 > AsH3 > SbH3 > BiH3

The electronegativity of N (N-3.0) is much higher that of H( H-2.1). Due to this, N-H bond is quite polar and hence NH3 undergoes intermolecular H-bonding.

On the other hand, both P and H have an electronegativity of 2.1. Therefore, P-H bond is non polar and hence PH3 does not form H-bonds.

Answered by Hanisha Vyas | 9th Oct, 2013, 06:57: PM

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