<span>The answer to the question is the option C. it cannot be physically broken down into different types of atoms. This means that the material is an element, which is a pure substance. Because an element is a pure substance that is formed by one only type of atoms. For example, gold is an element and all its atoms are of the same type. That is also true for any of the 118 elements of the periodic table. Compounds (other kind of pure substances) can be broken down into molecules (which contain different kind of atoms, but always in the same proportion) and mixtures (non pure substances) have different kind of substances.</span>
Answer: Equilibrium constant for this reaction is 
.
Explanation:
Chemical reaction equation for the formation of nickel cyanide complex is as follows.
 + 2OH^{-}(aq)](https://tex.z-dn.net/?f=Ni%28OH%29_%7B2%7D%28s%29%20%2B%204CN%5E%7B-%7D%28aq%29%20%5Crightleftharpoons%20%5BNi%28CN%29_%7B4%7D%5E%7B2-%7D%5D%28aq%29%20%2B%202OH%5E%7B-%7D%28aq%29)
We know that,
K = 
We are given that, 
and, 
Hence, we will calculate the value of K as follows.
K =
K = 
=
Thus, we can conclude that equilibrium constant for this reaction is .
Calcium carbide is a covalent compound.
Answer:
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