Answer:

Explanation:
Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.
It's an ionic bond! Potassium is a cation, or a metal with a positive charge, and fluoride is an anion, or a nonmetal with a negative charge.
A covalent bond is the bond between two nonmetals.
Hope this helped!
Answer: -
The rate decreases as the concentration of the reactants decreases
Explanation: -
A reaction involves change of the reactants into products.
Initially there is only reactants. So the rate if reaction is high.
After some time there are products. So the amount of reactant is less.
Reactions involve collisions of reactant molecules. As the reactant amount decreases, collisions between the reactants decreases. As such the rate of reaction decreases with the progress of the reaction.
Explanation:
Depression in Freezing point
= Kf × i × m
where m is molality , i is Van't Hoff factor, m = molality
Since molality and Kf remain the same
depression in freezing point is proportional to i
i= 2 for CuSO4 ( CuSO4----------> Cu+2 + SO4-2
i=1 for C2h6O
i= 3 for MgCl2 ( MgCl2--------> Mg+2+ 2Cl-)
So the freezing point depression is highest for MgCl2 and lowest for C2H6O
so freezing point of the solution = freezing point of pure solvent- freezing point depression
since MgCl2 has got highest freezing point depression it will have loweest freezing point and C2H6O will have highest freezing point