From a solubility curve the solubility of KNO3 at 40°C is about 63 g / 100 g of water.
That means that 100 g of water at 40°C can dissolve 63 g of KNO3.
A saturated solution is one that cannot dissolve more solute, because it already has reached the greatest concentration that it can hold.
Then, the mass of KNO3 that dissolves in 100 g of water is about 63 g.
No
Magnesium Chloride is MgCl2
The method I use to name ionic compounds is 'swap and drop'
Mg oxidation number is +2 and Cl oxidation number is -1
Mg^2+ Cl^-1
'swap'
Mg^1 Cl^2
'drop'
MgCl2
Answer: The correct option is 4.
Explanation: All the options will undergo some type of radioactive decay processes. There are 3 decay processes:
1) Alpha decay: It is a decay process in which alpha particle is released which has has a mass number of 4 and a charge of +2.

2) Beta-minus decay: It is a decay in which a beta particle is released. The beta particle released has a mass number of 0 and a charge of (-1).

3) Beta-plus decay: It is a decay process in which a positron is released. The positron released has a mass number of 0 and has a charge of +1.

For the given options:
Option 1: This nuclei will undergo beta-plus decay process to form 

Option 2: This nuclei will undergo beta-minus decay process to form 

Option 3: This nuclei will undergo a beta minus decay process to form 

Option 4: This nuclei will undergo an alpha decay process to form 

Hence, the correct option is 4.
2 HClO(aq) + Ca(OH)2(aq) = 2 H2O(l) + Ca(ClO)2(aq) is the balanced equation