Acids and Bases

Question 1

Acid

Answer 1

An acid is a substance that produces hydrogen ions in an aqueous solution

Question 2

Properties of Acids

Answer 2

1. Acids have a sour taste
2. Acids dissolved in water forms a solution which conducts electricity
3. Acids turns blue litmus paper red

Question 3

Reactions

Answer 3

1. Acid + reactive metal= salt + hydrogen
2. Acid + base/alkali= salt + water: White percipitate
3. Acid + carbonate= salt + water + carbon dioxide
4. Alkali + ammonium salt= salt + ammonia (NH3) + water

Question 4

Importance of water

Answer 4

Water will ionise hydrogen and hydroxide which will allow reaction to take place

Question 5

Bases

Answer 5

Bases are anything that has metal oxide and hydroxide in an aqueous solution

Question 6

Alkalis

Answer 6

Alkalis are substances that produces hydroxide ions, in an aqueous solution

Question 7

Properties of alkali

Answer 7

1. Alkali taste bitter and soapy
2. Alkalis turns red litmus paper blue

Question 8

PH scale

Answer 8

A pH scale is a set of numbers between 1 to 14 which indicates whether a solution is acidic, neutral and alkaline

Question 9

Plant

Answer 9

The pH value of the soil affects the growth of the plant
Plants grows best in a neutral or slightly acidic soil

Question 10

Concentration of pH

Answer 10

The concentration of a substance is related by how much hydrogen or hydroxide ions is present

Question 11

Universal indicator

Answer 11

Is a substance that change colour depending on the concentration of substance

Question 12

Neutralise the soil

Answer 12

By adding bases such as quicklime (Calcium oxide) or slacked lime (Calcium hydroxide) can help by reacting with the acids in the soil. Which will increase the pH of the soil. This process is known as ‘liming’ the soil.

Question 13

Which metals do not react with acids

Answer 13

1.Non-reactive metals such as copper or silver
2. Lead does not react with dilute hydrochloric acid and sulphuric acid
This layer is insoluble in water and quickly forms a coating around the metal

Question 14

Experiment for hydrogen

Answer 14

Place a lighted splint at the mouth of the test tube. The lighted splint will be extinguished with a ‘pop’ sound

Question 15

Experiment for carbon dioxide

Answer 15

Bubble gas through lime water, a white precipitate is formed, the precipitate dissolves upon further bubbling

Question 16

Experiment for ammonia

Answer 16

Place a piece of moisture red litmus paper at the mouth of the test tube, the moist red litmus paper turn blue