Page 362 - SUBSEC October 2017_Neat

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7. Which of the following are redox reactions?

I. 2H O (aq) → 2H O (l) + O (g)
2
2
2
2
II. Fe O (s) + 2Al (s) → Al O (s) + 2 Fe (s)
3
2
3
2
III. BaCl (aq) + H SO (aq) → BaSO (s) + 2HCl (aq)
4
2
2
4
(A) I and II only
(B) I and III only
(C) II and III only
(D) I, II and III

8. In the reaction between potassium manganate (VII) and potassium iodide in acid solution, the
following relevant half equations can be written:

2I → I + 2e-MnO + 8H + 5e → Mn + 4H O
+
-
-
-
2+
4
2
2

Which of the following is the overall balanced equation?

(A) MnO + 8H + 2I → Mn + 4H O + I 2
2+
+
-
−
4
2
(B) MnO + 8H + 2I → Mn + 4H O+ I + 2e -
-
+
2
2+
−
4
2
(C) 2MnO + 16H + 10I → 2Mn +8H O + 5I 2
+
-
2+
−
4
2
(D) 2MnO + 16H + 4I → 2Mn + 8H O + 2I
2+
-
+
−
4 2 2
9. Which of the following is NOT true about a dynamic equilibrium?

(A) It is reversible.
(B) Macroscopic properties are constant.
(C) Microscopic processes are in balance.
(D) It cannot be achieved in a closed system.
Item 10 refers to the following equation
C H NH (g) + HNO (aq) → C H OH (l) + H O (l) + N (g)
2 5 2 2 2 5 2 2
10. The volume of nitrogen gas collected at r.t.p. when 0.01mol of ethylamine completely reacts with
an excess of nitrous acid is

(A) 0.224 dm 3
(B) 0.24 dm 3
(C) 2.24 dm 3
(D) 2.40 dm 3
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02112010/CAPE/SPEC/2017