A redox reaction is a chemical reaction that transfers electrons between two reactants. This electron transfer can be identified by the change in the oxidation states of the reacting species.
Fuel combustion, metal corrosion, and even photosynthesis and cellular respiration all involve oxidation and reduction.
Download Class 11 Chemistry Worksheet on Chapter 8 Redox Reactions Set 4 PDF.
CBSE Class 11 Chemistry Chapter 8 Redox Reactions – Set 4
Q-1: Which of the following is not a redox reaction?
a) H2 + Cl2 → 2HCl
b) NaOH + HCl → NaCl + H2O
c) Photosynthesis
d) Cell respiration
Q-2: Which of the following is not correct for an electrochemical cell?
a) Convert electrical energy to chemical energy
b) Anode is the negative terminal
c) Anode is the positive terminal
d) Cathode is the positive terminal
Q-3: Which reaction involves neither oxidation nor reduction?
a) CrO42- → Cr2O72-
b) Cr → CrCl3
c) KMnO4 → MnO2
d) Fe → Fe2O3.xH2O
Q-4: Phosphorus has the oxidation state of +3 in
a) Orthophosphoric acid
b) Pyrophosphoric acid
c) Metaphosphoric acid
d) Phosphorous acid
Q-5: If a half cell reaction, C + e– → C– has a large negative reduction potential, it follows that
a) C is easily oxidised
b) C is easily reduced
c) C– is readily oxidised
d) C– is readily reduced
Q-6: What is a redox couple?
Q-7: Identify the species undergoing oxidation and reduction in the following reactions.
(i) CH4 + 2O2 → CO2 + 2H2O
(ii) 2H2S + O2 → 2S + 2H2O
(iii) CH2=CH2 + H2 → CH3-CH3
(iv) 2HgO +heat → 2Hg + O2
Q-8: Explain the following terms:
i) Oxidation potential
iii) Oxidising agent in terms of electrode potential
Q-9: What factors should be considered when selecting salt for a salt bridge?
Q-10: Split the following redox reactions in the oxidation and reduction half-reactions.
a) 2K + Cl2 → 2KCl
b) 2Al + 3Cu2+ → 2Al3+ + 3Cu
Q-11: The standard electrode potential corresponding to the reaction Au3+ (aq) + 3e– → Au(s) is 1.50 volt. Predict if gold can be dissolved in 1M HCl solution, and on passing H2 gas through the gold salt solution, metallic gold will be precipitated or not.
Q-12: In one litre of solution, 6.70 g of an alkali metal oxalate was dissolved. In order to make 10cm3 of this solution, 20cm3 of 0.01 M potassium permanganate solution in an acidic medium was needed. What is the atomic weight of alkali metal?
Q-13: How does Cu2O function as an oxidant and a reductant? Explain the change in oxidation numbers in each case using proper reactions.
Q-14: The electrode potentials of four metallic elements (A, B, C and D) are respectively +0.90, -0.86, +0.12, and +0.44 V. Sort them in decreasing electropositive order.
Q-15: On the basis of stoichiometry, determine the oxidation number of
i) Fe in Fe3O4 and Fe4[Fe(CN)6]
ii) Cl in CaOCl2
Q-16: Predict the reaction of 1N sulphuric acid with the following metals:
i) Zinc
ii) Silver
Given: E0(Ag+, Ag) = +0.80 volt and E0(Zn2+, Zn) = -0.76 volt
Q-17: State whether the following statements are True or False.
a) Reducing agents are electron acceptors.
b) Stock notation is used to name compounds of metals which involve variable oxidation states.
c) HgCl2 and SnCl2 cannot exist as such if present together in an aqueous solution.
Q-18: Cu2+ (aq) is treated with KI after 1.1g of copper ore sample is dissolved. Titration of the iodine liberated required 12.12cm3 of 0.1 M Na2S2O3 solution. What is the copper percentage in the ore?
Q-19: What is the difference in the definition of an equivalent in an acid-base reaction and an equivalent in an oxidation-reduction reaction?
Q-20: The standard electrode potentials of a few metals are given below:
Al(-1.66 V), Cu(+0.34 V), Li(-3.05 V), Ag(+0.80 V) and Zn(-0.76 V).
Which of these will behave as the strongest oxidising agent and which as the strongest reducing agent?
