Chapter 18: Chemical Changes (Part 2)

Which of the following is correct about an alkali?

• It is sour.

• It has a pH of less than 7.

• A product of its reaction with acids is water.

• It can be found in car batteries.

The following diagrams show four different experimental set-ups.

Which of the following will not result in a chemical change?

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Which of the following substances has the lowest pH value?

• detergent

• lemon juice

• pure water

• toothpaste

A few drops of Universal Indicator are added to a test tube containing sulfuric acid solution.

Which of the following represents the colour change most likely observed in the mixture as excess sodium hydroxide solution is added?

• Blue → Green → Red

• Blue → Red → Green

• Red → Green → Blue

• Red → Blue → Green

An excess of dilute sulfuric acid is added to each of the tubes shown in the diagram.

In which tube will there be no change of colour?

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Baking powder is dissolved in water. Universal indicator is added and the solution turns blue. A pH colour chart shows the solution to have a pH value of 9.

Baking powder is a …………………………………….

• strong acid

• strong alkali

• weak acid

• weak alkali

When an acid is dissolved in water, it turns red litmus paper blue.

• True

• False

An acid reacts with metal to produce 

• Carbon dioxide 
• Hydrogen gas
• Hydrogen gas and water 
• Salt and hydrogen gas 

When acids react with most metals, they produce hydrogen gas and salt.

• True

• False

Which of the following is not a neutralisation reaction?

• calcium hydroxide + hydrochloric acid

• potassium hydroxide + sufuric acid

• sodium hydroxide + nitric acid

• magnesium carbonate + hydrochloric acid