Answer:
The equilibrium law
Explanation:
According to the equilibrium law , when 
of any of the reactants or the products in the reaction at an equilibrium state, is changed, then it changes the composition of equilibrium mixture in order to minimize the effect of
Acetic acid (in excess) + 
⇄ 
+ water
is a reaction which involves the equilibrium. So to force the reaction towards the side of , one of the reactant is taken in excess. All this can be explained easily by applying the equilibrium law.
Solution = homogeneous mixture
Suspension = heterogeneous mixture
Colloid = homogeneous mixure
This will give substituted product which will be by SN2 mechanism
so here we will get product with inverted geometry
In SN2 mechanism the nucleophile attacks from back side and we always get product with inverted geometry
This is known as Walden inversion.
Because the calcium ion donates two electrons to achieve the stable state. So the layer of electrons decrease form 4 layers(2,8,8,2) to 3 layers(2,8,8). Thus, the radius of a calcium ion is smaller than a calcium atom.
