J.j Thomson electrons demo true indivisible sphere n Ernest central nucleas
Answer : The correct option is, 0.21 moles
Solution : Given,
Molarity of the solution = 0.85 M = 0.85 mole/L
Volume of solution = 250 ml = 0.25 L 
Molarity : It is defined as the number of moles of solute present in one liter of the solution.
Formula used :

Now put all the given values in this formula, we get the moles of solute of the solution.


Therefore, the moles of solute is, 0.21 moles
Crystallization
This is because insects that usually get stuck in sap tend to harden or crystallize, so they cannot get out. That is why it is a crystallization.
The term conservation of mass means that mass in any system can neither be created nor destroyed but can be transformed from one state to another.
<h3>What is the law of mass of conservation?</h3>
The law of conservation states that the mass in an isolated system can neither be created nor be destroyed but can be transformed from one form to another.
This means that when an element is involved in a chemical reaction, it's mass remains the same at the end of that reaction.
Learn more about mass here:
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This is because, only <span> weak van der Waals forces or weak London dispersion forces are present between the atoms of the </span><span>noble gases.
Hope this helps!</span>