Acid, Bases

When vinegar is added to eggshell, the shell dissolves and produces a gas. Which of the following explains the reaction?

• Eggshell is neutralized by acids.

• Eggshell dissolves in vinegar, but not in water.

• Vinegar contains an acid and eggshell contains a carbonate.

• Vinegar is very corrosive

The table shows the pH value of 4 soil samples.

Cabbages grow best in alkaline soil.

Which soil sample/s should a farmer use for growing cabbages?

• W, X and Y only

• W and X only

• Y and Z only

• Y only

Which of the following indicator could be used to distinguish between two samples of aqueous ammonia of pH 9 and sodium hydroxide solution of pH 12?

• A

• B

• C

• D

An excess of calcium hydroxide solution (alkali) is added to each of the test tubes as shown in the figure below. In which test tube will there be no change in colour?

• A

• B

• C

• D

When a drop of Universal Indicator is added to some dilute sulfuric acid, it turns red. When a solution X is added to the dilute sulfuric acid, the universal indicator turns blue. What could solution X be?

• distilled water

• dilute hydrochloric acid

• sodium chloride solution

• sodium hydroxide solution

Carbon dioxide was given off when vinegar was added to some eggshells. What does this tell you about the eggshells?

• They are acidic

• They are alkaline

• They are carbonates

• They are metallic

• Solutions P and Q

• Solutions R and S

• Solutions Q and T

• Solutions Q and R

Which of the following substances produces a gas when added into a beaker of acid?

• Sodium hydroxide

• Aqueous ammonia

• Potassium carbonate

• Toothpaste

Which of the following is a characteristic property of a strong alkali in aqueous solution?

• It reacts with metals to give a salt and hydrogen gas

• It reacts with acids to give a salt, carbon dioxide gas and water

• It turns litmus paper blue to red

• It turns universal indicator violet

The diagram shows an experiment on pH

The alkaline solution is slowly added to the beaker containing an acid. The alkali is added until the acid is neutralised. How does the colour of the Universal Indicator change?

• From red to blue

• From red to green

• From violet to pink

• From blue to green