b............................................
Alkaline earth metals are metals of group two. They are divalent metals and they have a highly negative reduction potential hence the metals are mostly extracted by electrolysis.
They are highly reactive metals. They react with water but do so less readily than alkali earth metals.
Owing to their high reactivity, they are seldom found free in nature. They always occur in combined state with other highly reactive nonmetals.
Answer:
Mole fraction for solute = 0.1, or 10%
Molality = 6.24 mol/kg
Explanation:
22.3% by mass → In 100 g of solution, we have 22.3 g of HCOOH
Mass of solution = 100 g
Mass of solute = 22.3 g
Mass of solvent = 100 g - 22.3g = 77.7 g
Let's convert the mass to moles
22.3 g . 1mol/ 46 g = 0.485 moles
77.7 g. 1mol / 18 g = 4.32 moles
Total moles = 4.32 moles + 0.485 moles = 4.805 moles
Xm for solute = 0.485 / 4.805 = 0.100 → 10%
Molality → mol/ kg → we convert the mass of solvent to kg
77.7 g. 1 kg / 1000g = 0.0777 kg
0.485 mol / 0.0777 kg = 6.24 m
Williamson synthesis is the most common way for obtaining ethers, called after its developer Alexander Williamson. It is an organic reaction of forming ethers from an organohalide and an alkoxide. The reaction is carried out according to the SN2 mechanism.
On the attached picture it is shown required alkoxide ion, <span>alkyl(aryl)bromide and the ether that forms from the reactants. </span>
Answer : The percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.
Explanation :
First we have to calculate the number of atoms in 5.5 wt% Pb and 94.5 wt% of Sn.
As, 207.2 g of lead contains
atoms
So, 5.5 g of lead contains
atoms
and,
As, 118.71 g of lead contains
atoms
So, 94.5 g of lead contains
atoms
Now we have to calculate the percent composition of Pb and Sn in atom.


and,


Thus, the percent composition of Pb and Sn in atom is, 3.21 % and 96.8 % respectively.