Question

1) 5 Fe2+ + MnO4- + 8 H+ yields 5 Fe3+ + Mn2+ + 4 H2O

In the equation above

A) H+ ions are reduced

B) Fe2+ ions are oxidized

C) H+ is the oxidizing agent

D) MnO4- is the reducing agent


2) What element is oxidized in the following reaction?

HNO3 + Cu yields Cu(NO3)2 + NO2 + H2O

A) H

B) N

C) O

D) Cu


3) What change would not result in a shift of the equilibrium position to the left?

2 A (g) + B (s) Two arrows stacked on top of each other. The top arrow points to the right. The bottom arrow points to the left. 3 C (g) + Energy

A) increasing the pressure

B) adding more of gas C to the system

C) removing some of A from the system

D) cooling the system


4) Which of the following reactions is not an example of an oxidation-reduction reaction?

A) 3Br2 + 2Ga yields 2GaBr3

B) H2S + Cl2 yields 2HCl + S

C) 2PbS + 3O2 yields 2PbO + 2SO2

D) K2Cr2O7 + KOH yields 2 K2CrO4 + H2O

Answer 1

1) Fe⁺² ions oxidized.

2) Copper

3) cooling the system

4) D)

K₂Cr₂O₇ + KOH --> 2 K₂CrO₄ + H₂O

Step-by-step explanation:

1) The oxidation is lose of electrons, in the given reaction the ferrous ions lose electron to form ferric ion and thus there is an increase in oxidation state of iron hence Fe⁺² is oxidized.

2) The oxidation is lose of electrons, the element oxidized undergoes increase in oxidation state. Copper is oxidized from zero oxidation state to +2.

3) If we increase pressure, the volume will decrease, which will increase moles per unit volume. Thus the system will shift in the direction where moles (gaseous) are less, hence it will shift to left.

If we add product then system will shift to left.

If we remove reactant, the system will shift to left.

It is an exothermic reaction, if we increase the temperature it will shift to left and if we decrease the temperature (cool the system) it will shift to right.

4) oxidation reduction reaction is one where an element undergoes oxidation and any other element undergoes reduction.

Here in case of K₂Cr₂O₇ + KOH --> 2 K₂CrO₄ + H₂O,

there is no change in oxidation state of any of the element.

Answer 2

1.) From the balanced chemical reaction, the correct answer is B. Fe2+ ions are oxidized to Fe3+.

2.) From the balanced chemical reaction, the correct answer is D. Copper is oxidized.

3.) From the balanced chemical reaction, the correct answer is B. Adding more of gas C to the system will shift the equilibrium to the left.

4.) The correct answer is option D, K2Cr2O7 + KOH yields 2 K2CrO4 + H2O