An anion is an ion with a negative charge. The minus sign, when attached to the end of an ionic compound, indicates that this has a negative charge, while a plus sign indicates a positive charge.
O2- is the only compound listed that satisfied this. It is the anion.
Answer is 02-
Liquids have free and fast moving particles. Liquids do not take a specific shape unless they are enclosed such as in a bottle. Anyway, since they are free flowing when they freeze, their movement becomes very slow. Eventually the particles will not have room to move as they used to and will be held in one place. The particles are still moving but they are only shaking or vibrating in the same place. You can't even tell this movement is happening, and that is what happens when liquid freezes.
Answer:

Explanation:
Hello there!
Unfortunately, the question is not given in the question; however, it is possible for us to compute the equilibrium constant as the problem is providing the concentrations at equilibrium. Thus, we first set up the equilibrium expression as products/reactants:
![K=\frac{[NO_2]^2}{[NO]^2[O_2]}](https://tex.z-dn.net/?f=K%3D%5Cfrac%7B%5BNO_2%5D%5E2%7D%7B%5BNO%5D%5E2%5BO_2%5D%7D)
Then, we plug in the concentrations at equilibrium to obtain the equilibrium constant as follows:

In addition, we can infer this is a reaction that predominantly tends to the product (NO2) as K>>>>1.
Best regards!
The answer to your question would be silicon. I hope this helped!!!