Chemistry of Aqueous Solutions

This assignment covers the chemistry of aqueous solutions, explaining key terms such as solubility, solute, solvent, and solution. It includes examples of miscible and immiscible substances, factors affecting gas solubility, and various acid-base reactions. The content also discusses the pH levels of different solutions and provides balanced chemical equations for reactions involving hydrochloric acid and sodium hydroxide.

CHEMISTRY OF
AQUEOUS SOLUTION

Explanation of terms soluble, solute, solvent, and solution
Soluble
Substance which have the ability to get dissolved in water or any other liquid substance is
termed as soluble. For example, in case of potassium chloride and water, potassium chloride is
easily soluble in water
Solute
The amount of the substance which is minor or less in any solution is known as Solute. In case of
potassium chloride and water, potassium chloride is solute.
Solvent
The substance in solution which is comparatively high quantity is known as Solute. In case of
potassium chloride and water, potassium chloride is solute.
Solution
A mixture of solute and solvent is termed as a Solution. Mixture of Potassium chloride and water
will give a solution of potassium hydroxide.
(ii). Give an example of a substance which is insoluble in water
Oil is the substance which is insoluble in water due to its significant properties that
differs it with water. Oil is non- polar while water is polar which create a mismatch between two
of it.
(iii). Explanation of terms miscible and immiscible with examples
Miscible liquids are the liquid which completely get mixed with solvent or solute without
forming any additional structure. For example, solution of ethanol and water is a miscible liquid.
Immiscible liquids generally form layers and do not get completely mixed into solution. For
example, mixture of Oil and water is an example of immiscible liquid.
b. List and explain three general factors that affect the solubility of a gas in water
Three general factors affecting solubility of gas in water are: Temperature, Pressure and Polarity
The solubility of gas in water decreases with the increased temperature. Gaseous substance
become more soluble in water if the temperature of surrounding is low. Gases exerted with high
pressure are generally soluble water. If water is stored under high pressure, then the gases

present in it will be highly soluble. Gaseous with same polarity as water are more likely to be
soluble. Non- polar gases do not get mixed with water.
Structure and formation of the hydrated potassium ion and the hydrated chloride ion
3. (α) An acidic, aqueous solution of hydrochloric acid, HCl (aq), has a pH of 2.5
(a) State which ions are present in the aqueous solution of hydrochloric acid.
Positively charged hydrogen ions and negatively charged chlorine ions.
(b) Write balanced chemical equations to show the reactions which would occur if the
solution of hydrochloric acid was mixed with:
Magnesium metal
Mg + 2 HCL→ MgCl2 + H2
Solid magnesium oxide
MgO + HCL → MgCl2 + H2O
Solid sodium carbonate, Na2CO3.
Na2CO3 + HCL→ NaCl + H2CO3
(c) Using answer to (a), explain why these reactions occur.
(β) An alkaline, aqueous solution of sodium hydroxide, NaOH, has a pH of 12.5
(a) State which ions are present in an aqueous solution of sodium hydroxide.
Cation Na+ and anion is OH-
(b) Write balanced chemical equations to show the reaction which would occur if the sodium
hydroxide solution was mixed with:
solid ammonium chloride, NH4Cl
NaOH + NH4Cl → NH3 + NaCl + H2O
a solution of hydrochloric acid, HCl
NaOH + HCl→ NaCl + H2O
(c). Using answer to (a), explain why these reactions occur

4. Boiling water has a pH of 6.1. Does this means that boiling water is acidic? Explain your
answer.
Boiling water with a pH of 6.1 does not mean that it is acidic, as the concentration of H+
ions are likely to increase which increases the pH level of boiling water.
5A (i) Complete and balance each of the equations below
(a) HNO3 + H2O ---------> H3O + NO3
(b) HNO3 + H2SO4 ---------> H2NO3 + HSO4
For each equation in (i), identify the conjugate pairs.
HNO3 is acid, conjugate acis is H3O+
H2O is base, conjugate base is NO3-
(iii) Give an example of a substance which forms an alkali in water
Magnesium oxide is a substance that give alkaline solutions with water.
b. The following equations represent various acid/base reactions. Complete and balance each
equation
(i) HCl (g) + H2O (l) ---------> H3O+ (aq) + (* Cl ) (aq)
(ii) NH3 (g) + H2O (l) ---------> (* NH4 ) (aq) + OH-(aq)
(iii) NH3 (g) + HCl (g) ---------> (* NH4Cl )(s)

REFERENCE
Books and Journals
Marcus, P., Protopopoff, É. and Maurice, V., 2019. Surface Chemistry and Passivation of Metals
and Alloys. InMechanics- Microstructure- Corrosion Coupling. (pp. 91-120). Elsevier.
Lu, S., Bi, H. and Liu, X., 2019. A phenomenographic study of 10th grade students’
understanding of electrolytes. Chemistry Education Research and Practice. 20(1).
pp.204-212.