Acid and alkali

Question 1

definition of an acid

Answer 1

acid is a substance that releases hydrogen ions when dissolved in water

Question 2

definition of an alkali

Answer 2

alkali is a substance that forms hydroxide ions when dissolved in water

Question 3

examples of acid

Answer 3

hydrochloric acidm = hcl
nitric acid
= HNO3
sulfuric acid
= H2S04
phosphoric acid
= H3PO4
ethanoic acid
= CH3COOH

Question 4

examples for alkali

Answer 4

Sodium hydroxide
= NaOH
Potassium hydroxide
= KOH
calcium hydroxide
= CAOH2
aqueous ammonia
= NH3

Question 5

Properties of acid

Answer 5

• sour taste
• corrosive
• conducts electricity
• changes the colour of an indicator

Question 6

Uses of acid

Answer 6

Sulfuric acid
1. manufacture of detergents, paints, dyes and plastic
2. used in car batteries
3. manufacture of agricultural fertilisers

Question 7

Properties of alkali

Answer 7

• soluble bases
• bitter and soapy taste
• conducts electricity
• change the colour of indicator

Question 8

PH scale

Answer 8

0 to 6 = acid
7 = neutral
8 to 14 = alkali

Question 9

Universal indiccator

Answer 9

• gives different colours in solutions of different ph
  STEPS
• add a few drops of ui into the solution
• the exact ph value can be found by comparing to the colour chart
• acidic = red, orange, yellow green
• alkali = purple, blue, pink, green

Question 10

Litmus paper

Answer 10

• cannot find out the exact ph value
• acidic = drip a strip of blue litmus paper into the solution, it should turn red
• alkali = drip a strip of red litmus paper into the solution, it should turn red
  Ammonia
• drip a strip of dampred litmus paper near the mout of the tube, if ammonia is present the red litmuspaper turns blue

Question 11

Chemical reaction

Answer 11

are chemical changes which involve a formation
of new products

Question 12

Neutralisation

Answer 12

acid + alkali = salt + water

Question 13

acid metal reaction

Answer 13

acid + reactive metal = salt + hydrogen gas

Question 14

acid carbonate reaction

Answer 14

acid + carbonate = salt + water + carbon dioxide

Question 15

Carbon dioxide test

Answer 15

• limewater test
  STEPS
• bubble the gas produce through the limewater
  if co2 is present, a white percipitate is formed

Question 16

Hydrogen gas test

Answer 16

• lighted splint test
  STEPS
• place a lighted splint near the mouth of the test tube
• if hydrogen gas is present, the lighted splint will estinguish with a pop sound