Acids and Alkalis KS3

Acids and Bases

What are the
properties of acids
and alkalis?
What is
neutralisation?
What are
indicators?

Acids
Acids produce hydrogen
ions, H+ when dissolved in aqueous solution (containing water) . For
example:

HCl(aq) → H+(aq) + Cl-(aq)

Acidic solutions have pH values less
than 7.

Alkalis
Alkalis form alkaline solutions in
water. Alkalis produce hydroxide
ions, OH- in aqueous solution. For
example:

NaOH(aq) → Na+(aq) + OH-(aq)

Alkaline solutions have pH values
greater than 7.

Multiple Choice

Alkalis are sources of

• hydrogen ions

• hydroxide ions

Multiple Choice

Acids taste

• fishy

• salty

• sour

• sweet

Multiple Choice

The name of acid in lemon juice is

• ethanoic

• lemonic acid

• citric acid

• sulfuric acid

Multiple Choice

Acids are sources of

• hydrogen ions

• hydroxide ions

Multiple Choice

Which one of these is an acid?

• salt water

• oven cleaner

• pure water

• vinegar

Multiple Choice

Which one of these is an alkali?

• lemon juice

• oven cleaner

• sugar solution

• vinegar

Multiple Choice

Indigestion tablets always contain

• acids

• antacids

• antibiotics

• indicators

Multiple Choice

Which of the following is a base?

• citric acid

• copper oxide

• pure water

• vinegar

Multiple Choice

_{What is the hazard shown in this hazard sign?}

• Explosive

• Corrosive

• Irritant

• High level Irritant

Neutral solutions
A neutral solution is neither acidic,
nor alkaline. A neutral solution has
a pH value of 7.

Indicators and the pH scale
The pH scale measures the acidity
or alkalinity of a solution. The pH
of a solution can be measured
using a pH probe, or estimated
using universal indicator and a
colour chart.

Universal indicator is one
example of an acid-alkali
indicator. Indicators show
whether a solution is acidic,
neutral (pH 7) or alkaline.

Multiple Choice

The colour of universal indicator in a substance that is very acidic is:

• green

• orange

• purple

• red

Multiple Choice

The reaction between an acid and an alkali is

• acidification

• condensation

• evaporation

• neutralisation

Multiple Choice

A solution of pH 3 is mixed with a solution of pH 9. The final pH could be

• 2

• 6

• 10

• 12

Multiple Choice

An acid reacted with an alkali to form a salt and water. Which of these are the reactants?

• acid and alkali

• acid and salt

• alkali and water

• salt and wate

Multiple Choice

A wasp sting has a pH of 10. You can treat a wasp sting with

• water

• toothpaste

• vinegar

• sodium hydroxide

Multiple Choice

The pH scale is a range from:

• 1-7

• 0-14

• 1-14

• 1-20

Multiple Choice

What is the only substance with a neutral pH of 7?

• Milk

• Orange Juice

• Water

• Blood

Multiple Choice

A solution with a pH of 3.6 would be an ...

• Acid

• Base

• Neutral

• Acid and Base

Multiple Choice

A solution with a pH of 8.6 would be a...

• Acid

• Base

• Neutral

• Acid and Base

Multiple Choice

According to the pH range which substance is more acidic than lemon juice

• Hydrochloric acid

• cabbage

• milk

Multiple Choice

Bleach is a strong alkali, what is the pH level of bleach?

• 13

• 10.5

• 1

• 2

Multiple Choice

Acid + Alkali --> Salt + Water

• neutralization reaction

• synthesis

• decomposition

• single displacement

Multiple Choice

A neutralization reaction will always produce...

• water & salt

• water

• salt

• water & carbon

Multiple Choice

A(n) ______ is a substance with a pH less than 7

• Acid

• Alkaline

• Base

• Buffer

Multiple Choice

The pH of pure water is

• 1

• 5

• 7

• 11

Multiple Choice

A(n) _______ is a substance with a pH greater than 7.

• Base

• Acid

• Buffer

• Water

Indicators are used to determine whether a solution is acidic or
alkaline. Acids react with metals, bases and carbonates to produce
salts. Neutralisation is the reaction between an acid and a base.

Neutralisation

Bases that are soluble in water are called alkalis and they dissolve in
water to form alkaline solutions. For example:
copper oxide is a base, but it is not an alkali because it is insoluble
in water. Sodium hydroxide is a base, and it dissolves in water so it is
also an alkali.

A neutralisation reaction is a reaction between an acid and a base.

A salt and water are produced.

Multiple Choice

The colour of litmus in sulfuric acid is:

• blue

• green

• purple

• red

Multiple Choice

Universal indicator is added to a solution. The solution turns purple. The solution contains

• citric acid

• hydrochloric acid

• sodium hydroxide solution

• only water

Multiple Choice

Nitric acid reacts with sodium hydroxide solution to form a salt and water. Which of the following is the correct word equation?

• nitric acid + sodium hydroxide + water

• nitric acid + sodium hydroxide --> sodium nitrate + water

• salt + water --> nitric acid + sodium hydroxide

• sodium nitrate + water --> nitric acid + sodium hydroxide

Multiple Choice

What colour is universal indicator in a strong alkali?

• Green

• Orange

• Purple

• Red

Multiple Choice

What colour is universal indicator in a neutral solution?

• Green

• Orange

• Purple

• Red

Multiple Choice

What colour is universal indicator in strong acid?

• Green

• Orange

• Purple

• Red

Multiple Choice

Strong acids and strong alkalis are.......

• Able to turn blue litmus paper red

• Corrosive

• Sour

• Sweet

Multiple Choice

Acids taste _________________.

• sour

• spicy

• sweet

• bitter

Multiple Choice

The image shows a PH scale. Which option indicates strong alkali?

• a

• b

• c

• d

Multiple Choice

The image shows a PH scale. Which option indicates strong acid?

• a

• b

• c

• d

Multiple Choice

The pH scale is a range from:

• 1-7

• 0-14

• 1-20

Multiple Choice

What is the substance with a neutral pH of 7?

• Milk

• Water

• Orange Juice

• Blood

Multiple Choice

Which substance is alkali?

• Toothpaste

• Lemon juice

• Vinegar

• Soft drink

Multiple Choice

Which substance is acid?

• Ammonia

• Toothpaste

• Vinegar

• Soap

Multiple Choice

Which pH levels indicated a strong acid?

• 1-3

• 4-6

• 8-11

• 12-14

Multiple Choice

Alkalis feel...

• Rough

• Soapy

• Granulated

• Smooth

Multiple Choice

Which of the following acids do we have in our stomach?

• Ethanoic acid

• Hydrochloric acid

• Nitric acid

• Sulphuric acid

Fill in the Blank

What is always made in a neutralisation reaction?

Multiple Choice

Vomit, vinegar and lemon juice are all examples of...

• acids

• alkalis

• neutral solutions

Multiple Choice

What is the meaning of the word 'acid'?

• Sour

• Bitter

• The ashes

• burn

Multiple Choice

What does this hazard symbol mean?

• toxic

• flammable

• corrosive

• explosive

Multiple Choice

These acids originated from plants except:

• Citric acid

• Hydrochloric acid

• Tartaric acid

• Ascorbic acid

Multiple Choice

A concentrated acid has _________ particles of acid per litre of water than a dilute acid

• the same number of

• more

• less

Multiple Choice

Where does the sour taste of vinegar comes from?

• nitric acid

• lactic acid

• ethanoic acid

• hydrochloric acid

Multiple Choice

What is used to tell if a substance is acid, alkaline or neutral?

• a thermometer

• a balance

• an indicator

• paper

Multiple Choice

These house hold items were made of ____________.

• acids

• alkalis

Multiple Choice

Which litmus paper would you use to tell if a substance is acidic?

• red

• blue

Multiple Choice

A purple colour when using universal indicator indicates the solution is _______________.

• neutral

• acidic

• alkali

• blackcurrant juice

Multiple Choice

What is the pH of a neutral solution?

• 1

• 14

• 5

• 7

Multiple Choice

What is the range of pH scale?

• 0 -14

• 1 - 14

• 1 - 6

• 12 - 14

Multiple Choice

What type of reaction occurs when you react an acid with an alkali?

• combustion

• decomposition

• no reaction

• neutralisation

Multiple Choice

An alkali is able to “cancel” out an acid. This process is also known as?

• balancing

• extraction

• overcome

• neutralisation

Multiple Choice

What is the name for a soluble base?

• acid

• alkali

• neutral solution

Multiple Choice

In an experiment some pupils found that baking soda had a pH of about 9. Some people claim this substance can be used to treat bee stings. Bee stings must be

• acidic

• alkaline

• neutral

• life threatening

Multiple Choice

Something that can dissolve in water is said to be...

• insoluble

• soluble

Multiple Choice

Milk of magnesia is a medicine used to treat indigestion. Milk of magnesia is most likely to be

• alkali

• neutral

• from a cow

• acidic

Multiple Choice

HCl, HNO₃ and H₂SO₄ are all acids. What element do all acids contain?

• oxygen

• hydrogen

• nitrogen

• sulfur

Multiple Choice

The image shows a PH scale. Which option indicates strong alkali?

• a

• b

• c

• d

Multiple Choice

Acids can react with metals or with bases to make what?

• salts

• water

• hydrogen

• oxygen

Multiple Choice

The image shows a PH scale. Which option indicates strong acid?

• a

• b

• c

• d

Multiple Choice

Acid + Metal --> Salt + ?

• water

• oxygen

• hydrogen

• carbon dioxide

Multiple Choice

What is the substance with a neutral pH of 7?

• Milk

• Water

• Orange Juice

• Blood

Multiple Choice

Acid + Base --> Salt + ?

• water

• hydrogen

• oxygen

• carbon dioxide

Fill in the Blank

Both acids and alkalis are _________________.

Multiple Choice

How would you remove an insoluble solid from a liquid?

• distillation

• chromatography

• filtration

• evaporation

Multiple Choice

What pH range would you get for an acid?

• 0-6

• 7

• 7-14

• 2-10