Acids, bases and salts

Question 1

Describe Alkaline in terms of pH

Answer 1

had a pH above 7

Question 2

Describe acid in terms of pH

Answer 2

has pH below 7

Question 3

Describe neutral in terms of pH

Answer 3

Neither acidic nor alkaline; neutral solutions have a pH of 7

Question 4

Acid + alkali –>

Answer 4

Salt + water

Question 5

Acid + metal

Answer 5

Salt + hydrogen

Question 6

Acid + Carbonate

Answer 6

Salt + Water + Carbon dioxide

Question 7

Acid + Oxide (bases)

Answer 7

Salt + Water

Question 8

characteristic properties of bases

Answer 8

• Have a pH above 7
• A base which is water-soluble is referred to as an alkali
• Turns red litmus paper blue

Question 9

What is the test for a carbonate? (tests to identify anions)

Answer 9

Add dilute acid
Effervescence, carbon dioxide produced

Question 10

What is the test for chloride (in solution)? (tests to identify anions)

Answer 10

Acidify with dilute nitric acid, then add
aqueous silver nitrate
Test results: white ppt

Question 11

What is the test for bromide (in solutions? (test for anions)

Answer 11

acidify with dilute nitric acid, then add
aqueous silver nitrate
Test result: cream ppt

Question 12

What is the test for nitrate (in solution)? (test for anions)

Answer 12

add aqueous sodium hydroxide, then
aluminium foil; warm carefully
Test result: ammonia produced

Question 13

What is the test for sulphate (in solution)? (test for anions)

Answer 13

acidify, then add aqueous barium nitrate
Test result: white ppt

Question 14

What is the test for ammonium? (test for aqueous cations)

Answer 14

effect of aqueous sodium hydroxide: Ammonia produced on warming

Question 15

What is the test for calcium? (test for aqueous cations)

Answer 15

effect of aqueous sodium hydroxide: white ppt., insoluble in excess
effect of aqueous ammonia: no ppt. or very slight white ppt.

Question 16

What is the test for copper (II)? (test for aqueous cations)

Answer 16

effect of aqueous sodium hydroxide: light blue ppt., insoluble in excess
effect of aqueous ammonia: light blue ppt., soluble in excess, giving a dark blue solution

Question 17

What is the test for iron (II)? (test for aqueous cations)

Answer 17

effect of aqueous sodium hydroxide: green ppt., insoluble in excess
effect of aqueous ammonia: green ppt., insoluble in excess

Question 18

What is the test for iron (III)? (test for aqueous cations)

Answer 18

effect of aqueous sodium hydroxide: red-brown ppt., insoluble in excess
effect of aqueous ammonia: red-brown ppt., insoluble in excess

Question 19

What is the test for Zinc? (test for aqueous cations)

Answer 19

effect of aqueous sodium hydroxide: white ppt., soluble in excess, giving a colourless solution
effect of aqueous ammonia: white ppt., soluble in excess, giving a
colourless solution

Question 20

What is the test for ammonia? (Test for gases)

Answer 20

turns damp red litmus paper blue

Question 21

What is the test for carbon dioxide?
(Test for gases)

Answer 21

turns limewater milky

Question 22

What is the test for chlorine? (Test for gases)

Answer 22

bleaches a damp litmus paper

Question 23

What is the test for hydrogen? (Test for gases)

Answer 23

‘pops’ with a lighted splint

Question 24

What is the test for oxygen? (Test for gases)

Answer 24

relights glowing splint

Question 25

What colour does lithium turn in the flame tests for metal ions?

Answer 25

Red

Question 26

What colour does sodium turn in the flame tests for metal ions?

Answer 26

Yellow

Question 27

What colour does potassium turn in the flame tests for metal ions?

Answer 27

Lilac

Question 28

What colour does copper (II) turn in the flame tests for metal ions?

Answer 28

Blue-green

Question 29

Name some properties of acids

Answer 29

- pH below 7 - Sour taste, corrosive - When added to water, they form positively charged hydrogen ions - Turn litmus paper red - Bases are usually oxides or hydroxides of metals - When alkalis are added to water, they form negative hydroxide ions (OH–)

Question 30

What is used to measure the pH?

Answer 30

Universal indicator

Question 31

What colour would the universal indicator if the pH was neutral?

Answer 31

Green

Question 32

What colour would the universal indicator if the pH was very acidic?

Answer 32

Red

Question 33

What colour would the universal indicator if the pH was a weak acid?

Answer 33

yellow/orange

Question 34

What colour would the universal indicator if the pH was very alkaline?

Answer 34

Purple

Question 35

What colour would the universal indicator if the pH was a weak alkaline?

Answer 35

Blue

Question 36

Are acids proton donors or proton acceptors?

Answer 36

Acids are proton donors as they ionise in solution producing protons, which are H+ ions

Question 37

Are bases proton donors or proton acceptors?

Answer 37

Bases are proton acceptors as they accept the protons which are donated by the acid