Acids and Alkalis

Extremely acidic

Neutral

Extremely alkaline

Weakly acidic

pH 1

pH 13

pH 7

pH 0

Red

Orange

Yellow

Violet

Making a solution more acidic

Making a solution more alkaline

Reacting an acid and alkali to reach pH 7

Adding water to an acid to make it stronger

Oven cleaner

Sea water

Fruit juice

Bleach

$pH$ 1

$pH$ 4

$pH$ 9

$pH$ 14

Vinegar

Lime (Calcium hydroxide)

Lemon juice

Battery acid

It lowers the $pH$.

It keeps the $pH$ constant.

It raises the $pH$.

It turns the solution into a strong acid.

Quickly pour a large amount of water into the acid.

Add the acid slowly to a large volume of water while stirring.

Boil the acid first to remove impurities.

Mix the acid with a strong alkali to make it safer before diluting.

2

7

10

14

Because alkalis can be corrosive to the skin

To make the alkali more concentrated

To help the alkali soak in

To change the color of your skin

The roots

The leaves

The seeds

The stem

It turns red

It turns green

It stays blue

It turns orange

To make the stomach more acidic

To neutralize excess stomach acid

To clean teeth

To add vitamins to food

The paper will turn red

The paper will turn blue

The paper will turn green

The paper will not change color

It stays blue

It turns red

It turns green

It dissolves

It likely tastes sour and feels watery

It likely tastes bitter and feels slippery

It likely tastes sweet and feels sticky

It likely has no taste and feels like oil

Yes, because acids keep red litmus paper red.

No, because neutral liquids also keep red litmus paper red.

Yes, because the smell confirms it is vinegar.

No, because red litmus only turns blue for acids.

It was a volatile acid.

It was an alkali that is stable under heat.

It was pure water with a gas dissolved in it.

The heating changed the substance from an acid to an alkali.

Universal indicator is a mixture of several different dyes.

Litmus paper is only made from synthetic chemicals.

Universal indicator only works for strong acids.

Litmus paper is more precise for measuring exact pH values.

Strong acid

Weak acid

Strong alkali

Neutral liquid

Oven cleaner

Distilled water

Lemon juice

Baking soda

Water

Salt

Acid

Indicator

Salt water

Red cabbage juice

Soapy water

Sugar solution

The salt is being formed

Water is boiling

A gas is being produced

The alkali is too strong

Using a thermometer

Using a pH probe and meter

Using red litmus paper only

Using a ruler

To speed up the salt formation

To compare the effects of acid and alkali against a neutral substance

To change the pH of the acid

To dissolve the indicator

Lemon juice (pH 2)

Bicarbonate of soda (pH 9)

Battery acid (pH 1)

Salt water (pH 7)

$HCl + Ca(OH)_{2} \rightarrow CaCl_{2} + H_{2}O$

$2HCl + Ca(OH)_{2} \rightarrow CaCl_{2} + 2H_{2}O$

$HCl + CaOH \rightarrow CaCl + H_{2}O$

$2HCl + CaOH \rightarrow CaCl_{2} + H_{2}$

$10\text{ cm}^{3}$

$15\text{ cm}^{3}$

$20\text{ cm}^{3}$

$30\text{ cm}^{3}$

Put your books away

Wash your hands thoroughly with soap and water

Turn off the lights

Tell your friend goodbye

It might make your face dirty

You could transfer harmful acids or alkalis to your sensitive skin or eyes

It is considered bad manners

It will make your goggles foggy

By the shape of the bottle

By checking the hazard symbols and labels on the bottle

By seeing if the liquid is bubbling

By checking how heavy the liquid looks

To save the school money

To prevent waste and reduce the risk of large spills

Because the bottle is too heavy to carry

So other students have nothing to use

Only one person wears goggles while the others watch

Everyone in the group wears goggles and follows safety rules

The person doing the mixing wears goggles, but the person recording does not

Goggles are only needed if someone in the group is clumsy

The substance is a liquid

The substance is a gas stored under high pressure

The substance is very light

The substance must be kept in a vacuum

Leave it on the bench for the technician to find

Rinse it thoroughly with water as instructed and place it in the wash area

Wipe it with a dry paper towel and put it back in the cupboard

Throw it in the bin if it looks too dirty to clean

The room will become too hot.

The $CO_2$ can displace oxygen, creating a suffocation risk.

The $CO_2$ will turn back into acid on the walls.

The $CO_2$ will cause the floor to become slippery.

Taste a small drop to see if it is sour (acidic).

Dip your finger in and see if it feels soapy (alkali).

Treat it as a highly hazardous waste and inform the teacher/technician.

Mix it with a known acid to see if it reacts.

To allow them to see the teacher better.

To enable them to move away quickly in case of a spill or accident.

To prevent them from falling asleep in class.

Because sitting down makes the chemicals more dangerous.