iGCSE Chemistry 0620 Extended - 8.3 Group VII properties- Exam Style Questions Paper 2- New Syllabus
▶️ Answer/Explanation
Correct Answer: A (1 and 3)
Explanation: A more reactive halogen displaces a less reactive halide from solution. Reactivity decreases down Group VII: Cl > Br > I.
1. KBr + Cl₂: Cl displaces Br (Cl more reactive) → displacement occurs. ✅
2. KBr + I₂: I is less reactive than Br → no displacement. ❌
3. KI + Cl₂: Cl displaces I (Cl more reactive) → displacement occurs. ✅
4. KCl + I₂: I is less reactive than Cl → no displacement. ❌
✅ Displacement occurs in mixtures 1 and 3.
▶️ Answer/Explanation
At room temperature and pressure, iodine is a grey-black solid. (Bromine is a red-brown liquid, chlorine is a pale yellow-green gas).
✅ Answer: (B)
✅ Answer: (B)
▶️ Answer/Explanation
When chlorine reacts with potassium bromide: \(\mathrm{Cl_2 + 2KBr \rightarrow 2KCl + Br_2}\). The bromine produced gives an orange colour in aqueous solution. This is a displacement reaction where the more reactive halogen (chlorine) displaces the less reactive halogen (bromine).
(A) is false — Group VII halogens are diatomic (\(\mathrm{F_2, Cl_2, Br_2, I_2}\)).
(B) is false — reactivity increases down Group I, so caesium is more reactive than lithium.
(C) is false — melting points decrease down Group I.
✅ Answer: (D)
(A) is false — Group VII halogens are diatomic (\(\mathrm{F_2, Cl_2, Br_2, I_2}\)).
(B) is false — reactivity increases down Group I, so caesium is more reactive than lithium.
(C) is false — melting points decrease down Group I.
✅ Answer: (D)