Discussion Forum



1)

When O2  is absorbed on a metallic surface, electron transfer occurs from the metal to O2. The true statement (s)  regarding this adsorption is(are)  


A) $O_{2}$ is physisorbed

B) heat released

C) Occupancy of $^{*}\pi_{2\rho}$ of $O_{2}$ is increased

D) bond length of $O_{2}$ is increased

Answer:

Option B,C,D

Explanation:

Since adsorption involves electron transfer from metal to O2, it is chemical adsorption not physical adsorption at the (a) is incorrect. Aggregation is point focus which involves some bonding between adsorbent and adsorbate, hence exothermic. The last occupied molecular orbital in O2  is   $\pi ^{*}2p$. Hence, electron transfer from metal to oxygen will increase the occupancy of$\pi ^{*}2p$    molecular orbitals. Also, increase in occupancy of $\pi ^{*}2p$ orbitals will decrease bond order and hence increase bond length of O2.