(a(i))[1]
State which of R, S, T or U is the compound.
(a(ii))[1]
State which one conducts electricity in the solid state.
(a(iii))[1]
State which substance has the lowest melting point.
(a(iv))[1]
State which substance is a macromolecule.
(a(v))[1]
State which substance can act as a catalyst.
(b)[2]
Name the brown substance formed when aqueous potassium iodide reacts with aqueous chlorine, and suggest the reason for its formation.
(c)[1]
Which compound below is also found in many fertilisers? Tick one box.
(d)[2]
Explain why farmers avoid adding calcium hydroxide (slaked lime) to the soil at the same time as fertilisers that contain ammonium salts.