CAIE IGCSE Chemistry Acids with Metals Bases and Carbonates

Practise predicting acid reactions with metals, bases and carbonates, writing balanced equations and matching gas, dissolution or colour observations.

Exam points

predict salt and hydrogen for a typical acid-metal reaction and describe effervescence
predict salt and water for neutralisation with a base and identify when excess solid remains
predict salt, water and carbon dioxide for carbonates and use fizzing as gas evidence

[Maximum number: 2]

Sulfuric acid can be manufactured from the raw materials sulfur, air and water. The process can be divided into four stages.
stage 1 converting sulfur into sulfur dioxide
stage 2 converting sulfur dioxide into sulfur trioxide
stage 3 converting sulfur trioxide into oleum, $\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{7}$
stage 4 converting oleum into sulfuric acid
stage 1

Sulfuric acid reacts with a hydrocarbon called benzene to produce benzenesulfonic acid, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{3} \mathrm{H}$ . Benzenesulfonic acid is a strong acid which ionises to produce hydrogen ions, $\mathrm{H}^{+}$ , and benzenesulfonate ions, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{3}{ }^{-}$ .

Write a chemical equation for the reaction between benzenesulfonic acid and sodium carbonate, $\mathrm{Na}_{2} \mathrm{CO}_{3}$ .

$\mathrm{Na}_{2} \mathrm{CO}_{3}+2 \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{3} \mathrm{H} \rightarrow 2 \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{3} \mathrm{Na}+\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O}$

formula of $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{3} \mathrm{Na}$ all formulae correct and balancing correct

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7.1.1—Characteristic properties of acids in question 1