At low temperature , say below ( − 11 ∘ C ) nitrogen dioxide exist as a trimer. Options: A . &nbspTrue B . &nbspFalse C . &nbspNO2 D . &nbspAll of these

Answer: Option B : B At low temperatures like ( − 11 ∘ C ) nitrogen dioxide exist as a dimer, not trimer. This is an observation. 2 N O 2 ⇌ N 2 O 4 (Brown gas) (Colorless solid) N 2 O 4 is a diamagnetic, colourless substance. The equilibrium shown above becomes more and more favoured in the forward direction as we lower the temperature. Above ( 21 ∘ C ) , N O 2 is a reddish-brown gas and below ( 21 ∘ C ) , N O 2 is a yellowish-brown liquid. On cooling below ( − 9 ∘ C ) it dimerizes into the colourless N 2 O 4 in the . For the dimer, in the liquid and gaseous states, the following structure is proposed. The dimer formation can be attributed to the overlap of the s p 2 hybrid orbitals containing the “odd” electrons. The consequent N—N bonding molecular orbital exhibits weak bonding character. In fact, the N—N bond energy is only about 60 kJ. m o l − 1 .

At low temperature, say below (−11∘C) nitrogen dioxide exist as a trimer.

Question

At low temperature, say below

(- 11^{\circ} C)

nitrogen dioxide exist as a trimer.

Options:

A . True

B . False

C . NO2

D . All of these

Answer: Option B
:
B
At low temperatures like

(- 11^{\circ} C)

nitrogen dioxide exist as a dimer, not trimer. This is an observation.

2 N O_{2} ⇌ N_{2} O_{4}

(Brown gas) (Colorless solid)

N_{2} O_{4}

is a diamagnetic, colourless substance. The equilibrium shown above becomes more and more favoured in the forward direction as we lower the temperature. Above

(21^{\circ} C)

N O_{2}

is a reddish-brown gas and below

(21^{\circ} C)

N O_{2}

is a yellowish-brown liquid. On cooling below

(- 9^{\circ} C)

it dimerizes into the colourless

N_{2} O_{4}

in the . For the dimer, in the liquid and gaseous states, the following structure is proposed.

At Low Temperature, Say Below (−11∘C) Nitrogen Dioxide E...

The dimer formation can be attributed to the overlap of the

s p^{2}

hybrid orbitals containing the “odd” electrons. The consequent N—N bonding molecular orbital exhibits weak bonding character. In fact,
the N—N bond energy is only about 60 kJ.