F4 pH and its measurement

The pH of an acidic substance is

• lower than pH7.

• greater than pH7.

• equal to pH7.

• not determined.

Which of the following substances are acidic (more than ONE answer)?

• soap

• distilled water

• orange juice

• soft drink

Which of the following is an acid-base indicator?

• litmus solution

• hydrochloric acid

• sodium hydroxide

• K₃Fe(CN)₆