The answer is: [B]: "ionic salt" .
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Note: There is no "sharing of electrons" among the elements in this compound; so this compound in NOT a "covalent molecule".
However, there is ionic bonding: Cu²⁺ and Cl⁻ ; to form: "CuCl₂" .
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Cumulene is an alkene hydrocarbon that has two or three double bonds. It is also known as allene. The simplest cumulene is butatriene. It is a rigid hydrocarbon due to the presence of double bonds.
Answer: The orbital that overlap are p/p overlap, s/sp2 overlap, sp/sp2 overlap and sp/sp orbital.
Answer : The equilibrium concentration of
at
is,
.
Solution : Given,
Equilibrium constant, 
Initial concentration of
= 0.260 m
Let, the 'x' mol/L of
are formed and at same time 'x' mol/L of
are also formed.
The equilibrium reaction is,

Initially 0.260 m 0 0
At equilibrium (0.260 - x) x x
The expression for equilibrium constant for a given reaction is,
![K_c=\frac{[H_3O^+][C_2H_3O_2^-]}{[HC_2H_3O_2]}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BH_3O%5E%2B%5D%5BC_2H_3O_2%5E-%5D%7D%7B%5BHC_2H_3O_2%5D%7D)
Now put all the given values in this expression, we get

By rearranging the terms, we get the value of 'x'.

Therefore, the equilibrium concentration of
at
is,
.