Acids and bases

Holly has an unknown substance in a beaker. She wants to determine the relative pH of the unknown substance. She places a piece of blue litmus paper into the substance, and the litmus paper stays blue.

The substance in the beaker

• is a base

• is an acid

• have neutral pH

• doesn't have pH

Which of the following word pairs correctly completes the sentence below?

_______ are corrosive substances characterized as having a strong smell, a sour taste, and a _______.

• acid pH less than 7

• acid pH greater than 7

• base pH less than 7

• base pH greater than 7

Litmus paper can be used to determine the _______ of a substance

• relative volume

• relative pH

• temperature

• chemical formula

Which of the following statements is correct?

• Blue litmus paper turns red when placed in a base.

• Red litmus paper turns blue when placed in a base.

• Blue litmus paper stays blue when placed in an acid.

• Red litmus paper stays red when placed in a base.

The pH of a solution is tested, and it is found to be a basic solution. Of the following choices, what could the pH have been?

• 3

• 7

• 9

• 5

Human blood has a pH between 7.35 and 7.45. Which of the following best describes human blood?

• strongly acidic

• slightly acidic

• strongly basic

• slightly basic

When using pH paper, the pH of a solution can be determined by looking at the _______ of the paper

• texture

• mass

• colour

• length

What would be considered the weakest base?

• 8

• 7.8

• 11.6

• 14

Many cleaning solutions are bases. Which of the following is a property of most bases?

• feels slippery

• white color

• can only be liquid

• tastes sour

Pure water has a pH of 7. Pure water _______.

• is a base

• is a neutral substance

• could be either an acid or a base

• is an acid