Acids, Bases, and Salts - SS1 Chemistry Past Questions and Answers - page 5
In a neutralisation reaction between nitric acid (HNO3) and calcium hydroxide (Ca(OH)2), the salt produced is:
Calcium nitrate (Ca(NO3)2)
Calcium hydroxide (Ca(OH)2)
Calcium carbonate (CaCO3)
Calcium chloride (CaCl2)
What is the pH of a neutral solution?
0
7
14
It varies depending on the specific neutral solution
When an acid reacts with a metal carbonate, the products formed are:
Salt and water
Salt and carbon dioxide
Salt and oxygen
Salt and hydrogen gas
Which of the following salts is produced in a neutralisation reaction between hydrochloric acid (HCl) and ammonia (NH3)?
Sodium carbonate (Na2CO3)
Sodium chloride (NaCl)
Ammonium chloride (NH4Cl)
Calcium chloride (CaCl2)
When an acid reacts with a metal, the products formed are:
Salt and water
Salt and carbon dioxide
Salt and hydrogen gas
Salt and oxygen
What is the general formula for a salt?
AB
ABO
AB2
AB2O
The pH of a basic solution is:
Less than 7
Greater than 7
Equal to 7
It depends on the specific basic solution
Explain the concept of neutralisation reactions and provide examples of their applications. Describe the formation and properties of salts in neutralisation reactions.
Neutralisation reactions occur when an acid reacts with a base to produce salt and water. The reaction involves the transfer of protons (H+) from the acid to the hydroxide ions (OH-) from the base, resulting in the formation of water and a salt compound.
Applications of Neutralisation Reactions:
- Antacid: Neutralisation reactions are used to alleviate symptoms of acidity in the stomach. Antacid medications, such as calcium carbonate (CaCO3), react with excess stomach acid to neutralise it.
- Water Treatment: Neutralisation reactions are employed in water treatment processes to adjust the pH of acidic or alkaline water sources. Acidic water is treated with alkaline substances, like sodium hydroxide (NaOH), to neutralise it and make it safe for consumption.
- Agricultural Practices: Neutralisation reactions are utilised in agricultural practices to modify soil pH. Lime (calcium hydroxide, Ca(OH)2) is added to acidic soils to neutralise the acidity and promote healthy plant growth.
Formation and Properties of Salts:
During a neutralisation reaction, the combination of the acid and base results in the formation of a salt. Salts are ionic compounds composed of positive ions (cations) derived from the base and negative ions (anions) derived from the acid.
Properties of salts include:
- Ionic Nature: Salts exist as a crystal lattice structure composed of positive and negative ions held together by ionic bonds.
- Solubility: Salts can be soluble or insoluble in water, depending on their chemical composition. Soluble salts dissociate into ions when dissolved in water, while insoluble salts remain as solid particles.
- Melting and Boiling Points: Salts generally have high melting and boiling points due to the strong electrostatic forces between ions.
- Conductivity: When dissolved in water or molten state, salts can conduct electricity as they dissociate into ions that can move and carry electric charge.
- Colour and Taste: Salts can exhibit various colours, and their taste depends on the specific ions present. For example, sodium chloride (NaCl) is white and tastes salty.