Question

Question: Lewis structures can be used to understand why some molecules react in certain ways. Write the Lewis structures for the reactants and products in the reactions described below.

a. Nitrogen dioxide dimerizes to produce dinitrogen tetroxide.

b. Boron trihydride accepts a pair of electrons from ammonia, forming

NH₃BH₃.

Give a possible explanation for why these two reactions occur.

Short answer

Answer

Nitrogen dioxide dimerizes to produce dinitrogen tetroxide-

Boron trihydride accepts a pair of electrons from ammonia, forming NH₃BH₃

Step-by-step solution

Step1: a. Nitrogen dioxide dimerizes to produce dinitrogen tetroxide:

N₂O₄ is a colourless gas, whereas NO₂ is a reddish brown gas.

The dimerization of (shown ABOVE)NO₂ is an exothermic reaction, according to the thermodynamic data for this system.

As the temperature rises, the above reaction equilibrium changes to the left, producing a larger concentration ofNO₂ and darkening the reddish brown colour inside the tube. Cooling the reaction, on the other hand, pushes the equilibrium to the right, creating more colourlesN₂O₄.

b. Boron trihydride accepts a pair of electrons from ammonia, forming: NH3BH3 

The diammoniate salt $\left[H_{2}B\left(N{H}_3\right)2\right]\mathbf{+}\mathit{B}{\mathit{H}}_{\mathbf{4}}$ is produced primarily by the reaction of diborane with ammonia. When a borane adduct is used instead of diborane, the major result is ammonia borane.