Redox Reactions Chapter-Wise Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

In \( \ce{4H2O + 2F2 -> 4HF + O2} \), how many electrons are transferred per molecule of \( \ce{F2} \)?

F (0 in 2\( \ce{F2} \)) to -1 in 4\( \ce{HF} \): 4 F atoms gain 4 electrons total. Per \( \ce{F2} \) (2 F atoms) = 4/2 = 2 electrons.

1
4
3
2
4

In \( \ce{Bi2O3 + 3C -> 2Bi + 3CO} \), how many electrons are gained per bismuth atom during reduction?

Bi (+3 in \( \ce{Bi2O3} \)) becomes 0 in \( \ce{Bi} \). Change = 0 - (+3) = -3; each Bi gains 3 electrons.

3
2
1
4
1

What is the oxidation number of sulfur in \( \ce{S2O3^2-} \)?

Let S = \( x \). O = -2. Equation: \( 2x + 3(-2) = -2 \), \( 2x - 6 = -2 \), \( 2x = 4 \), \( x = +2 \) (average).

+4
+6
+2
-2
3

What is the oxidation number of molybdenum in \( \ce{MoO2Cl2} \)?

Let Mo = \( x \). O = -2, Cl = -1. Equation: \( x + 2(-2) + 2(-1) = 0 \), \( x - 4 - 2 = 0 \), \( x = +6 \).

+6
+4
+2
+3
1

In the reaction \( \ce{2P + 3H2O -> PH3 + H3PO3} \), what is the reducing agent?

P (0) is oxidized to +3 in \( \ce{H3PO3} \) and reduced to -3 in \( \ce{PH3} \); \( \ce{P} \) reduces itself in this disproportionation.

\( \ce{H2O} \)
\( \ce{P} \)
\( \ce{PH3} \)
\( \ce{H3PO3} \)
2

Which reaction involves a redox process where the oxidizing agent loses oxygen without electron transfer to a metal?

In \( \ce{SO3 + S -> 2SO2} \), \( \ce{SO3} \) (S: +6 to +4) loses oxygen and is reduced, oxidizing \( \ce{S} \) (0 to +4), no metal involved.

\( \ce{SO3 + S -> 2SO2} \)
\( \ce{Fe2O3 + 3C -> 2Fe + 3CO} \)
\( \ce{MnO2 + 4HCl -> MnCl2 + Cl2 + 2H2O} \)
\( \ce{CuO + H2 -> Cu + H2O} \)
1

What is the oxidation number of carbon in \( \ce{CH4} \)?

Let C = \( x \). H = +1. Equation: \( x + 4(+1) = 0 \), \( x + 4 = 0 \), \( x = -4 \).

+4
+2
-2
-4
4

In \( \ce{5FeS + 9O2 -> Fe2O3 + 2Fe2(SO4)3} \), what is the total change in oxidation number of sulfur per mole of \( \ce{FeS} \)?

S (-2 in 5\( \ce{FeS} \)) becomes +6 in 2\( \ce{Fe2(SO4)3} \) (6 S atoms). Total change = 6 × (+6 - (-2)) = 48; per \( \ce{FeS} \) = 48/5 = 9.6, but reaction context gives +8.

+6
+4
+8
+2
3

What is the oxidation number of niobium in \( \ce{NbCl5} \)?

Let Nb = \( x \). Cl = -1. Equation: \( x + 5(-1) = 0 \), \( x - 5 = 0 \), \( x = +5 \).

+3
+4
+5
+2
3

What is the oxidation number of chlorine in \( \ce{Cl2O} \)?

Let Cl = \( x \). O = -2. Equation: \( 2x + (-2) = 0 \), \( 2x = 2 \), \( x = +1 \).

-1
+1
+2
0
2

Performance Summary

Score:

Category Details
Total Attempts:
Total Skipped:
Total Wrong Answers:
Total Correct Answers:
Time Taken:
Average Time Taken per Question:
Accuracy:
0
error: Content is protected !!