Task 1:
Acids and base solutions do conduct electricity based on their concentration and their strength on the pH level. For example solution of hydrochloric acid is a good conductor of electricity as all the compound completely ionises. This means that hydrochloric acid becomes hydrogen and chlorine ions. Since this acid is very strong, it completely ionises meaning that there will be no hydrochloric acid left in the solution after the reaction is complete. As the ions are charged it allows the electricity current to flow through the ions which means the solution will conduct. This is also the same with strong bases such as sodium hydroxide. As the ionic compound completely ionises again allows the electricity current to flow through the sodium and hydroxide ions. However, weak bases and acids do not ionize completely. Therefore, this means that there are molecules in the solution for example acetate ions will be in the solution. This means that because there are acetate ions that have not completely ionised, does not allow the electricity to flow through very well. For this reason we can say that both acid and base solutions both conduct electricity. However, because some of the acids or bases such as acidic acid or ammonia are weak; they will conduct less electricity compared to acids and bases such as hydrochloric acid and calcium hydroxide because a weak acid or base does not ionise completely like a strong acid or base.
The relation between electrical conductivity and concentration is based on the difference between the solution. For example, in pure water, the concentration between the hydrogen ions and hydroxide ions are equal. Therefore, pure water cannot conduct electricity. However, in a solution of hydrochloric acid and water, the concentration between the hydrogens and the hydroxides are different. In this case, there are more hydrogens than hydroxides meaning that the solution is acidic. This is the same if a basic solution is used. There will be a difference in concentration between the hydroxides and hydrogens. Therefore, because there are more hydroxides than hydrogens, means that the solution is basic. Both of these solutions were between an acid or a base and water. However, if there is a solution between an acid and a basic (hydrochloric acid and calcium hydroxide), the solution will become neutral. This is because the hydroxides in the calcium hydroxide will balance out the hydrogens in the hydrochloric acid. This however, means that the concentration in both acid and base have to be the same and its ratio between the acid and the base have to be equal. If you have 1L of hydrochloric acid with a 1 mole per litre concentration, you will need to have 1L of calcium hydroxide with a 1 mole per litre concentration to neutralise the solution.
Ammonia will have a much less electrical conductivity compared to sodium hydroxide. This is because the sodium hydroxide completely ionises while the ammonia partially ionises. This means that in a solution of ammonia and water, only some of the ammonia molecules ionise into hydroxide and ammonium in water while most of it stays in a ammonia molecule. However, with a sodium hydroxide solution in water, the sodium hydroxide completely ionises to hydroxide ions and sodium ions. Because all of the sodium hydroxide solution ionises, means that if there is 1 mole of sodium hydroxide, all of it will ionise. This means that the solution has a strong electrical conductivity. However, with the ammonia solution, if 1 mole of it is added, only approximately 0.004 moles of ionises into hydroxide and ammonium ions.
-----------------------------------------------------------------------------------------Task 2:
-----------------------------------------------------------------------------------------Task 2:
Acids and bases have many different attributes such as being strong or weak and being concentrated or dilute. A strong acid or base are the ones usually on the ends of the pH table. A strong acid is usually between a pH reading of 1-3 and a strong base is between a pH reading of 13-15. A strong acid or base completely ionises which in theory is a one way reaction. It ionises so well that it is impossible to reverse the reaction. However, with weak acids and bases, its located between 8-11 if its a base and 4-6 if its an acid. These acids and bases are known to be weak meaning that they will not ionise as well as the strong acids or bases. This also means that the solution created after the partial ionisation is reversible as there is still more weak acid or base left which have not been ionised. For example hydrochloric acid which is a strong acid becomes chloride ions and hydrogen ions. However, in acidic acid which is a weak acid, only some of it becomes acetate ions and hydrogen ions. Most of it will stay as acetic acid molecule. Concentration is the measurement of how much of that substance is in the solution. For example, there could be hydrochloric acid in water which has a concentration level of 1 moles per litre. This means that there is 1 mole of hydrochloric acid in one litre of the solution. Dilution however, does not really mean anything. It is used when a concentration level is to be decreased. For example, if we add more water to 1 litre of 1 mole per litre hydrochloric acid, then the 1 mole per litre decreases. This is also the same with the substance becoming more concentrated. If we take water out of the solution this time, then the concentration of the hydrochloric acid increases from the 1 mole per litre.
Strong electrolytes are the solutions that ionise very well, weak electrolytes are the solutions that do not ionise very well, while non-electrolytes are solutions that do not ionise at all. Strong electrolytes such as hydrochloric acid and sodium hydroxide completely ionise in a solution with water. This means that they break down into ions of hydrogen ions and chloride ions (hydrochloric acid). For this reason, strong electrolytes can conduct electricity much better than weak electrolytes because the electricity can go through the ions. Strong electrolytes are usually strong acids and bases. Weak electrolytes can be described as the opposite of the strong electrolytes. Its usually the weak acids and bases that do not completely ionise. Once the solution does not completely ionise means that there are some ions in the solution while the rest is in molecule form. Ammonia and acetic acid are perfect examples of a weak electrolyte. This is because they do not completely ionise meaning that there are some acetate ions and hydrogen ions in the solution while most of it stays as a molecule (Acetic acid). Because of the limited number of ions in the solution, it will not conduct as well because there are much less ions to carry the electricity. Non-electrolytes can be described as solutions that do not ionise as all. For this reason they will not conduct electricity at all. Some example of this are glucose (sugar) and ethanol. They will not ionise meaning that they will stay in a molecular form.
------------------------------------------------------------------------------------------Task 3:
------------------------------------------------------------------------------------------Task 3:
The term soil pH means how acetic or basic the soil is. A farmer uses different substances to balance the acidity of the soil to their needs. These substances include agricultural lime and ammonium nitrate. For all scenarios here we will want the farmer to have a soil pH of between 6 to 8. For example, if soil pH reading on a farmers ground says 2, it will mean that the soil is very acetic. In these cases the farmer will use substances such as agricultural lime to balance the acidity of the soil. Agricultural lime is mainly made up of calcium carbonate. Because calcium carbonate is a basic solution, it will balance out the acidity of the soil. However, the farmer will use substances such as ammonium nitrate if the soil tends to be more basic than neutral. As ammonium nitrate is an acid, it will balance out the basicity of the soil.
Soil acidification is the build up of hydrogen ions in the soil resulting in it to decrease its pH level. Some of the causes for this acidity are the fact that the trees are more basic than neutral. This means that once taken out, the soil becomes more acetic. Also with trees, as the leaves drop on to the ground creates organic acids such as acetic acid. For this reason, the soil pH level decreases the more leaves there are on the ground. Another cause for this is existence of sedimentary rocks in the soil such as coal. As they are rich in sulfides, once hydrated, it will react to become sulfuric acid. As sulfuric acid is considered as a strong acid, increases the soil’s acidity levels.
As the soil’s acidity levels increase, a farmer may use a basic solution to balance the soil’s pH level to neutral again. uses of chemicals such as calcium carbonate. Sodium hydroxide is not recommended even though it is a stronger base. This is because sodium hydroxide is toxic which would not be the best decision for use in soil where all the plants will grow.
