Properties of Acids and Bases

Match each term to its definition.

• Base

• A compound that tastes sour and has a lower pH than water

• pH

• A solution with a pH of 7

• pH scale

• The measure of the acidity or basicity of a solution

• Acid

• A compound that tastes bitter and has a higher pH than water

• Neutral solution

• A scale ranging from 0-14 that measures how acidic or basic a solution is

Label the image of the pH scale.

a

b

c

Acid

Neutral Solution

Base

What properties of acids and bases would help you identify them?

Answer explanation

Acids taste sour, have a lower pH than water, and are not slippery to the touch. Bases taste bitter, have a higher pH than water, and are often slippery to touch.

What do you know about pH?

Answer explanation

It measures the acidity or basicity of a solution. It can be measured on a pH scale that ranges from 0–14. Water is neutral at around 7.0, acids are listed below 7.0, and bases are listed above 7.0.

Tags

NGSS.MS-PS1-2

pH measures the acidity or basicity of an aqueous solution. The pH scale shows the range of pH values from 0 to 14 and measures the concentration of Hydrogen ions in a solution. Which observations could you make, based on this information and image?
(Select 2 correct answers.)

• A pH value of 7 is neutral; water is neutral.

• Acids are from 8-14.

• Bases are from 0-6.

• An example of an acid is a banana.

• An example of a base is lemon juice.

Match the following substances to their pH values according to the pH scale diagram:

• Bananas

• 4

• Household ammonia

• 8

• Drain cleaner

• 11

• Blood

• 0

• Battery acid

• 14

Students in a science class are using a universal indicator to test the pH of various substances. The color key for the universal indicator is provided. Which of the following is the most reasonable conclusion for the students to make based on these observations when comparing and contrasting the substances to the pH of water?

• The reaction with the universal indicator produced a purple color; therefore, the substance is more acidic than water.

• The reaction with the universal indicator produced an orange color; therefore, the substance is more acidic than water.

• The reaction with the universal indicator produced a red color; therefore, the substance is neutral, like water.

• The reaction with the universal indicator produced a yellow-green color; therefore, the substance is more basic than water.

What characteristics would you expect something acidic to have?

• High pH and bitter taste

• High pH and sour taste

• Low pH and slippery feel

• Low pH and sticky feel

Students in a science class were comparing and contrasting the pH levels of two different substances to water. Each student made a statement about whether each substance was an acid or a base and why.

• -Ishaan said that Substance 1 has a higher pH than water, so it must be an acid. 

• -Olivia said that Substances 1 and 2 are both neutral, because their pH levels are close to that of water. 

• -Natsuki said that Substance 2 has a lower pH than water, so it must be an acid.  

• -Camila said that Substance 2 has a pH lower than water, so it must be a base.

• Which student's statement is correct?

• Ishaan

• Olivia

• Natsuki

• Camila

Students tested the pH of a substance and found it had a pH of 11. The pH of water is 7. Is the substance an acid or base, and what other properties should you expect the substance to have?

• The substance is an acid and would also have a sour taste and a sticky feel.

• The substance is an acid and would also have a bitter taste and a slippery feel.

• The substance is a base and would also have a sour taste and a sticky feel.

• The substance is a base and would also have a bitter taste and a slippery feel.