Answer: If the solubility of sodium chloride is 36 grams per 100 grams of water then 5.8 moles of NaCl dissolved in 1 L of water solution would be considered unsaturated.
Explanation:
A solution which contains the maximum amount of solute is called a saturated solution. Whereas a solution in which more amount of solute is able to dissolve is called an unsaturated solution.
Now, the number of moles present in 36 g of NaCl (molar mass = 58.4 g/mol) is as follows.

This shows that solubility of sodium chloride is 36 grams per 100 grams of water means a maximum of 0.616 mol of NaCl will dissolve in 100 mL of water.
So, a solution in which number of moles of NaCl are less than 0.616 mol per 100 mL then the solution formed will be an unsaturated solution.
- As 5.8 moles of NaCl dissolved in 1 L (or 1000 mL) of water. So, moles present in 100 mL are calculated as follows.

- Moles present in 100 mL of water for 3.25 moles of NaCl dissolved in 500 ml in water are as follows.

- Moles present in 100 mL of water for 1.85 moles of NaCl dissolved in 300 ml of water are as follows.

Thus, we can conclude that if the solubility of sodium chloride is 36 grams per 100 grams of water then 5.8 moles of NaCl dissolved in 1 L of water solution would be considered unsaturated.
Answer:
1.99 M
Explanation:
The molar mass of sodium thiosulfate (solute) is 158.11 g/mol. The moles corresponding to 110 grams are:
110 g × (1 mol/158.11 g) = 0.696 mol
The volume of solution is 350 mL = 0.350 L.
The molarity of sodium thiosulfate is:
M = moles of solute / liters of solution
M = 0.696 mol / 0.350 L
M = 1.99 M
Answer : Hg (Mercury)
Explanation : In the given series of elements Na falls after the Cu in the reactivity series, for Pb it also falls after Cu, and for Mg it is the same.
Only Hg which is mercury can spontaneously donate its electrons to copper in the solution because it falls before Cu in the reactivity/activity series.