SECTION A
Answer ALL the questions in this section.
You should aim to spend no more than 20 minutes on this section.
For each question, select one answer from A to D and put a cross in the box. If you change your mind, put a line through the box and then mark your new answer with a cross.
1 Which mixture results in a displacement reaction?
A – Iron and copper (II) sulfate solution
B – Lead (II) nitrate solution and sodium iodide solution
C – Dilute hydrochloric acid and sodium hydroxide solution
D – Zinc and magnesium sulfate solution
(Total for Question 1 = 1 mark)
ANSWER
A – Iron and copper (II) sulfate solution
Analysis of Option/Explanation
Option A
Fe + CuSO4 →FeSO4 + Cu; In this reaction “Fe” being more reactive than “Cu” displaces it from its compound by forming “FeSO4” and leaving “Cu” alone. Hence, it is a displacement reaction.
Option B
Pb (NO3)2 + 2NaI→PbI2 + 2NaNO3 (precipitate); It is reaction for checking of halide solution. In this due to presence of halide (NaI), a yellow precipitate is formed indicating precipitation reaction.
Option C
HCl + NaOH → NaCl +H2O, in this reaction acid react with a base to form salt and water which indicates neutralization reaction.
Option D
Zn + MgSO4→ No reaction; in this, no reaction occur since “Zn” is less reactive than “Mg” and cannot displace it.
