Answer:
0 M.
Explanation:
Hello,
In this case, the undergoing reaction is:
![M(NO_3)_2+NaCN\leftrightarrow [M(CN)_4]^{-2}+NaNO_3](https://tex.z-dn.net/?f=M%28NO_3%29_2%2BNaCN%5Cleftrightarrow%20%5BM%28CN%29_4%5D%5E%7B-2%7D%2BNaNO_3)
Nonetheless, it only matters the reaction forming the given complex:
![M^{+2}+4CN^-\leftrightarrow [M(CN)_4]^{-2}](https://tex.z-dn.net/?f=M%5E%7B%2B2%7D%2B4CN%5E-%5Cleftrightarrow%20%5BM%28CN%29_4%5D%5E%7B-2%7D)
In such a way, the formation constant turns out:
![K_F=\frac{[[M(CN)_4]^{-2}]_{eq}}{[M^{+2}]_{eq}[CN^{-}]_{eq}^4}](https://tex.z-dn.net/?f=K_F%3D%5Cfrac%7B%5B%5BM%28CN%29_4%5D%5E%7B-2%7D%5D_%7Beq%7D%7D%7B%5BM%5E%7B%2B2%7D%5D_%7Beq%7D%5BCN%5E%7B-%7D%5D_%7Beq%7D%5E4%7D)
Now, one could assume that the initial concentrations of the ions equals the original compounds concentrations:
![[M^{+2}]_0=0.150M;[CN^-]_0=0.820M](https://tex.z-dn.net/?f=%5BM%5E%7B%2B2%7D%5D_0%3D0.150M%3B%5BCN%5E-%5D_0%3D0.820M)
In such a way, we modify the formation constant in terms of the change 
due to the reaction progress:
Now, solving for :
The feasible solution is 0.15M which will lead to an equilibrium concentration of M⁺² of 0M
![[M^{+2}]_{eq}=0.15M-0.15M=0M](https://tex.z-dn.net/?f=%5BM%5E%7B%2B2%7D%5D_%7Beq%7D%3D0.15M-0.15M%3D0M)
This fact has sense since the formation constant is very large.
Best regards.
The answer is 4 million, there are about 9-10 million unique organic compounds that are known to exist
Answer : Option B) All atoms of a single substance are identical.
Explanation : The scientist John Dalton proposed the atomic theory which had the postulates as follows.
i) All matter/substances consists of indivisible particles known as atoms.
ii) Atoms of the same element/substance are similar in mass,shape and size, but differ from the atoms of other elements.
iii) Atoms obey the law of conservation of energy which says atoms cannot be created or destroyed.
iv) Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form any compound atoms.
v) Atoms of same element can combine in ratio with more than one to form two or more compounds.
vi) The atom is considered to be the smallest unit of matter that can take part in a chemical reaction
