Indicators

Multiple Choice

When a blue litmus paper turned red when placed in a solution, what can you deduce about the nature of the solution?

• the solution is acidic

• the solution is alkali

• the solution can be acidic or neutral

Multiple Choice

When a red litmus paper turned blue when placed in a solution, what can you deduce about the nature of the solution?

• the solution is acidic

• the solution is alkali

• the solution can be alkali or neutral

Multiple Choice

When acid is added, indicator X turned blue.

When alkali is added, indicator X turned pink.

Which substance is added for indicator X to turn pink?

• orange juice

• detergent

• pure water

• vinegar

Multiple Choice

Phenolphthalein is another indicator that turned colourless for the pH range from 1 to 10.

It is pink for the pH range from 10.1 to 14.

What would be the colour of the indicator in water?

• colourless

• pink

Multiple Choice

When a few drops of universal indicator is added to an acid with pH 1, what colour would you observe?

• red

• yellow

• green

• purple

Multiple Choice

When a few drops of universal indicator is added to an acid with pH 3, what colour would you observe?

• red

• yellow

• green

• purple

Multiple Choice

When a few drops of universal indicator is added to water, what colour would you observe?

• red

• yellow

• green

• purple

Multiple Choice

When a few drops of universal indicator is added to alkali with pH 14, what colour would you observe?

• red

• yellow

• green

• purple