Answer:

Explanation:
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In this case, according to the given information it will be firstly necessary to set up the chemical equation taking place:

We infer we need to calculate the moles of NH3 by using both of the moles of N2 and H2 at the beginning, in order to identify the limiting reactant:

Thus, since hydrogen yields the fewest moles of ammonia, we conclude that we are just able to yield 4 moles of NH3.
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It's the first option choice on Plato
The answer should be B, ionic bond.
Ionic bond is the bonding between a metal and a non-metal. While covalent bond is the bond between non-metals, and metallic bond is the bond between metals.
Since Na, sodium, is a metal, and Cl, chlorine, is a non-metal, the bond formed between them is an ionic bond. Sodium gives up an electron to chlorine inside this bonding.