CAIE A-Level Chemistry AS Practical Assessment Skills Questions

Aqueous bromine reacts with methanoic acid to form hydrogen bromide and carbon dioxide gas.

The table shows the oxidation numbers of bromine and carbon in the species involved in this reaction.

Suggest one change you would observe, ignoring temperature changes, when bromine reacts with methanoic acid.

The reaction between $\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}(\mathrm{aq})$ and HCl(aq) is monitored at constant temperature.

Fig. 4.1 shows how the concentration of HCl(aq) varies with time.

Explain why the rate of reaction cannot be monitored accurately by measuring the volume of $\mathrm{SO}_{2}(\mathrm{~g})$ produced in this reaction.

J dissolves in water to give an aqueous solution K.
K gives a dense white precipitate when aqueous silver nitrate is added.
When heated with aqueous potassium hydroxide, K gives off a gas that turns moist universal indicator paper blue.

What is J ?

When dealing with a spillage of metallic sodium it is important that no toxic or flammable products are formed.

Which material should be used if there is a spillage of metallic sodium?