MDCAT/ECAT/FSC Chapter-wise High-Yield Chemistry MCQs Interactive Quiz on Electrochemistry and Oxidation Number Set I

Welcome to Inamjazbi Learn Chemistry! 🎉 This ultimate Class 11 Chemistry MCQs test covers Electrochemistry and Oxidation Number. Test your knowledge with interactive questions, get instant feedback on each answer, and see your final score at the end! 🧠Keep track of your score and challenge yourself!

Whether you are preparing for exams or just love Chemistry, this quiz is perfect for sharpening your concepts. Ready, set, answer! ⚡

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🔥🌟 Grand Chemistry Interactive  MCQs Quiz Test on Electrochemistry and Oxidation Number for Class FSC/MDCAT/ECAT Set I  🧪💡 | Learn & Practice!

1. The outer body of dry cell serves as anode, it is made up of

a) Copper

b) Lead

c) Zinc

d) Iron

✅ Correct Answer: (c)
👉 The outer body (container) of a dry cell acts as the anode and it is made of zinc metal, which undergoes oxidation during the cell reaction.
🔥 The cathode is typically a carbon rod surrounded by a mixture of MnO₂ and carbon powder.
🔎 Composition and Construction of Dry Cell
➡️1. Zinc vessel (Outer body………….……; Acts as anode
➡️2. carbon or graphite rod ……………...; acts as cathode (Centrally placed)
➡️3. manganese dioxide (40%) ………….; Acts as cathode, helps to depolarize electrodes to produce steady current
➡️4. Ammonium Chloride(8%) and Zinc chloride (8%) ……; Acts as electrolyte giving necessary ions for conduction
➡️5. Glycerin or Starch (4%) …………; serves to retains moisture
➡️6. Carbon powder (40%) ……………; serves to increase the surface area of graphite cathode
➡️7. copper cap ………………………; for conduction of electricity
➡️8. Zinc container internally lined with porous paper works as a separator.
➡️Electrolyte
The region between cathode and anode is filled a paste of MnO₂, carbon, NH₄Cl and ZnCl₂.

2. The conduction of electricity through an electrolytic solution is due to the flow of

a) Electrons

b) Ions

c) Atoms

d) Molecules

✅ Correct Answer: (b)
👉 The conduction of electricity through an electrolytic solution is called electrolytic conduction which is due to the movement of free floating ions of electrolyte.
In contrast, the electronic or metallic conduction of electricity through metal or graphite is due to free moving valence electrons.

3. During electrolysis, the reaction that takes place at anode is

a) Oxidation

b) Reduction

c) Simultaneous oxidation and reduction

d) Hydrolysis

✅ Correct Answer: (a)
👉 In electrochemical cells (whether electrolytic or Galvanic cell), oxidation always takes place at anode while reduction occurs at cathode.

4. The strongest oxidizing agent in the electro chemical series is:

a) Li

b) H₂

c) Cu

d) F₂

✅ Correct Answer: (a)
🔎 The strength of an oxidizing agent depends on its standard reduction potential (E°) in the electrochemical series.
🔎 The strongest oxidizing must have highest reduction potential.
👉 In ECS (electrochemical series), F₂ has the highest standard reduction potential (+2.87 V), it most readily gains electrons, making it the strongest oxidizing agent.
➡️ (a) Li → Lithium has a very negative reduction potential (–3.04 V). That means Li⁺ ions are easily reduced to Li metal, but metallic Li itself is a strong reducing agent, not an oxidizing agent.
➡️ (b) H₂ → Standard hydrogen electrode (SHE) is defined as 0 V. Hydrogen is neither the strongest oxidizer nor reducer; it’s the reference.
➡️ (c) Cu → Copper has a positive reduction potential (+0.34 V for Cu²⁺/Cu), but it’s moderate. Not the strongest oxidizer.
➡️ (d) F → Fluorine has the highest reduction potential (+2.87 V) in the electrochemical series. This means F₂ is reduced most easily to F⁻, so F₂ is the strongest oxidizing agent. ✅

5. Galvanized rod of iron is coated with:

a) Nickel

b) Zinc

c) Chromium

d) Carbon

✅ Correct Answer: (b)
🔎 Galvanized iron is coated with zinc. Galvanizing is the type of electroplating involving coating of zinc on baser metals like iron.

6. Oxidation number of Cr in Na₂Cr₂O₇, is:

a) +3

b) +6

c) +8

d) +12

✅ Correct Answer: (b)
➡️Oxidation number of Na = +1
➡️Oxidation number of O = −2
➡️In a neutral compound, sum of oxidation numbers of all atoms is equal to zero.
👉 2(Na) + 2Cr + 7(O) = 0 ⇒ 2(+1) + 2Cr + 7(−2) = 0 ⇒ 2 + 2Cr + (−14) = 0 ⇒ 2 + 2Cr −14 = 0 ⇒ 2Cr −12 = 0 ⇒ 2Cr = +12 ⇒ Cr = +12/2 = +6 👈

7. Which of the following half cell reaction show oxidation?

a) Fe³⁺ → Fe²⁺

b) Cl₂→ 2Cl⁻

c) SO₄²⁻ → SO₃²⁻

d) Zn → Zn²⁺

✅ Correct Answer: (d)
🔥 Oxidation means increase in oxidation number of atom during a reaction.
👉 The conversion of Zn (ON =0) to ion (ON = +2) involves loss of 2 electrons which is manifested by the 2 units increase in oxidation number.
🔎 Rule of thumb
⚡Oxidation = loss of electrons (increase in oxidation number).
⚡Reduction = gain of electrons (decrease in oxidation number).
➡️ (a) Fe³⁺ (+3) → Fe²⁺ (+2): Oxidation number decreases → reduction, not oxidation.
➡️ (b) Cl₂ (0) → Cl⁻ (–1): Oxidation number decreases → reduction, not oxidation.
➡️ (c) SO₄²⁻( S = +6) → SO₃²⁻( S = +4): Oxidation number decreases → reduction, not oxidation.
➡️ (d) Zn (0) → Zn²⁺ (+2): Oxidation number increases → oxidation ✔️✅

8. Fuel cell is a typical Galvanic cell which is based on the reaction between:

a) Nitrogen & oxygen

b) Hydrogen & oxygen

c) Methane & oxygen

d) Hydrogen & zinc

✅ Correct Answer: (b)
🔎 A fuel cell is an electrochemical cell that generates electrical energy from fuel via an electrochemical reaction.
👉 A hydrogen oxygen fuel cell is a unique type of Galvanic cell based on the reaction between hydrogen and oxygen to produce water and the heat released in the reaction is used to produced electricity.
➡️Cathode …………… Platinum coated porous graphite
➡️Anode ……………… Platinum coated porous graphite
➡️Electrolyte ……..... Concentrated alkaline electrolyte like KOH
➡️Hydrogen gas …... fed to anode side (where it reacts with four OH⁻ to produce 4 water molecules)
➡️Oxygen gas ……… Fed to the cathode side (where it reacts with water to produced four OH⁻ ions)

9. In Zn-SHE voltaic cell, the half reaction occurs at anode is

a) Zn²⁺+ 2ē → Zn

b) Zn → Zn²⁺ + 2ē

c) 2H⁺ + 2ē → H₂

d) H₂ → 2H⁺ + 2ē

✅ Correct Answer: (b)
👉In Zn-SHE voltaic cell, zinc oxidizes to zinc ion (Zn²⁺) at anode (while SHE or hydrogen ion reduces to H₂ gas at cathode).
🔎 Key Insight
➡️ Anode = site of oxidation (loss of electrons).
➡️ In a Zn–SHE cell, zinc acts as the anode.
➡️ Therefore, zinc metal is oxidized to Zn²⁺ ions. ✅👈

10. This statement is not correct for lead storage battery:

a) It can be recharged

b) It is a primary battery

c) Anode is made up of lead

d) Cathode is made up of lead oxide

✅ Correct Answer: (b)
Lead storage battery is a secondary cell.

11. The sum of the oxidation numbers of all the carbons in C₆H₅CHO is

a) +2

b) 0

c) +4

d) –4

✅ Correct Answer: (d)
⚡Let x be the oxidation state of C then oxidation state of C in C₆H₅CHO is calculated as
⚡6x + 5(+1) + x +1 + (−2) = 0 ⇒ 7x + 6−2 = 0 ⇒ 7x + 4 = 0 ⇒ 7x = −4 ⇒ x = −4/7
⚡As there are 7 carbon atoms present in the compound, the sum of oxidation state of all the carbon atoms will be 7x,
⚡i.e. −7 x 4/7 = −4

12. The oxidation number of N in N₂H₅⁺

a) –3

b) –2

c) –1

d) +2

✅ Correct Answer: (b)
Compound: N₂H₅⁺ (protonated hydrazine ion)
Formula: 2 nitrogen atoms + 5 hydrogens, overall charge = +1.
2N + 5(H) = +1 ⇒ 2N + 5(+1) = +1 ⇒ 2N + 5 = +1 ⇒ 2N = +1 −5 ⇒ 2N = −4 ⇒ N = −4/2 = −2 👈 (Each nitrogen has oxidation number –2.)

13. In which of the following compounds the oxidation number of carbon is maximum?

a) HCHO

b) CHCl₃

c) CH₃OH

d) C₁₂H₂₂O₁₁

✅ Correct Answer: (b)
The maximum oxidation number of carbon among the given compounds is in CHCl₃ (option b), where carbon is +2. 👈
🔎 (a) HCHO (Formaldehyde)
H = +1 (two hydrogens → +2)
O = –2
➡️Let C = x Equation: x+2+(−2)=0⇒ x = 0 👉 Carbon oxidation number = 0
🔎 (b) CHCl₃ (Chloroform)
H = +1
Cl = –1 (three chlorines → –3)
➡️Let C = x Equation: x + 1 + (−3)= 0 ⇒ x = +2 👉 Carbon oxidation number = +2 ✅(Maximum oxidation number)
🔎 (c) CH₃OH (Methanol)
H (3 hydrogens in CH₃ + 1 in OH) = +4
O = –2
➡️Let C = x Equation: x + 4 +(−2) = 0 ⇒ x =–2 👉 Carbon oxidation number = –2
🔎 (d) C₁₂H₂₂O₁₁ (Sucrose)
H = +1 (22 hydrogens → +22)
O = –2 (11 oxygens → –22)
➡️Let C = x Equation: x + 22 + (−22) = 0 ⇒ x = 0 👉 Carbon oxidation number = 0.

14. The oxidation number of hydrogen in MH₂ is

a) +1

b) +2

c) –2

d) –1

✅ Correct Answer: (d)
🔎 The compound MH₂ represent metal hydrides which are mostly ionic where M is a metal usually alkali or alkaline earth metals.
👉 In ionic metal hydrides of s-block elements, hydrogen usually has oxidation number –1 (because metals are less electronegative than hydrogen, so hydrogen behaves like an anion).
🔎 Example:
NaH, CaH₂ → H = –1.

15. Oxidation number of iodine varies from

a) –1 to +1

b) –1 to +7

c) +3 to +5

d) –1 to +5

✅ Correct Answer: (b)
🔎 Iodine belongs to halogens of group VIIA of the periodic table.
In halogens, oxidation number varies from -1 (as in iodide, I⁻) to +7 (as in periodate, IO₄⁻).
👉 Iodine can show a wide range: –1, 0, +1, +3, +5, +7 depending on the compound.

16. The atomic number of an element which shows the oxidation state of + 3 is

a) 7

b) 9

c) 13

d) 33

✅ Correct Answer: (c)
🔎 The elements of group IIIA (₅B, ₁₃Al etc.) and group IIIB (₂₁Sc, ₃₉Y etc.) shows +3 oxidation states.

17. The most common oxidation state of an element is –1. The number of electrons present in its outermost shell is

a) 7

b) 1

c) 6

d) 5

✅ Correct Answer: (a)
🔎 The oxidation state -1 indicates that element tends to gain one electron. The elements with 7 valence electrons (halogens of group VIIA) have a tendency to gain one electron to complete their octet.

18. Nitrogen shows different oxidation states in the range

a) 0 to +5

b) –3 to + 5

c) –5 to + 3

d) –3 to + 3

✅ Correct Answer: (a)
👉 Nitrogen shows variety of oxidation states ranging from 0 to +5.
👉 Oxidation states of nitrogen
➡️Minimum: –3 (in NH₃, amines, nitride ion N³⁻).
➡️Maximum: +5 (in HNO₃, NO₃⁻).
👉 Nitrogen can show a wide range: –3, –2, –1, 0, +1, +2, +3, +4, +5.

19. The oxidation number and covalency of phosphorus in the phosphorus molecule (P₄) are respectively

a) 0 and 3

b) +4 and 4

c) 0 and 4

d) +4 and 3

✅ Correct Answer: (a)
➡️Oxidation number = the imaginary charge an atom appears to have if all bonds were considered ionic.
➡️Covalency = number of covalent bonds formed by an atom.
👉 The oxidation number of phosphorus in P₄ is zero. However, the valency of phosphorus in P₄is three because each P atom is attached to three other P atoms.
➡️ P₄ is an elemental molecule. In any free element, the oxidation number = 0. 👉 Oxidation number of phosphorus = 0
➡️ In P₄, each phosphorus atom is bonded to three other phosphorus atoms (tetrahedral structure). Therefore, the covalency of phosphorus = 3.

20. Oxidation number of P in Mg₂P₂O₇ is

a) +3

b) +2

c) +5

d) –3

✅ Correct Answer: (c)
➡️ Oxidation number of Mg = +2
➡️ Oxidation number of O = −2
👉 2(Mg) + 2P + 7(O) = 0 ⇒ 2(+2) + 2P + 7(−2) = 0 ⇒ +4 + 2P−14 = 0 ⇒ 2P −10 = 0 ⇒ 2P = +10 ⇒ P = +10/2 = +5👈
🔎🧠 Concept Booster
🔥 In chemistry, pyrophosphates are phosphorus oxyanions that contain two phosphorus atoms in a P–O–P linkage.
🔥 A number of pyrophosphate salts exist, such as disodium pyrophosphate (Na₂H₂P₂O₇) and tetrasodium pyrophosphate (Na₄P₂O₇), among others.
🔥 Often pyrophosphates are called diphosphates.
🔥 The parent pyrophosphates are derived from partial or complete neutralization of pyrophosphoric acid.
🔥 The pyrophosphate bond is also sometimes referred to as a phosphoanhydride bond, a naming convention which emphasizes the loss of water that occurs when two phosphates form a new P–O–P bond.

21. The change in oxidation state of nitrogen in the following reaction is
Zn + HNO₃ → Zn(NO₃)₂ + N₂O + H₂O

a) 0 to +2

b) +5 to +4

c) +5 to +1

d) +5 to –2

✅ Correct Answer: (c)
➡️Oxidation number of N in HNO₃ = +5
➡️Oxidation number of N in N₂O = +1
👉 Change in oxidation number of N = +5 to +1
👉 Nitrogen goes from +5 (in HNO₃) → +1 (in N₂O)

22. Identify the element which can have highest oxidation numbers.

a) B

b) B

c) Cl

d) C

✅ Correct Answer: (c)
🔎 Highest oxidation state corresponds to group number.
👉 Since Cl is present in group VIIA, it shows highest oxidation state of +7.

23. In which of the following substances does sulphur exhibits is highest oxidation state?

a) S₈

b) SO₂Cl₂

c) Na₂S₄O₆

d) Na₂S₂O₃

✅ Correct Answer: (b)
🔎 Sulphur belongs to group VIA.
🔎Highest oxidation number is equal to group number.
👉 Hence highest oxidation number of sulphur will be +6.
➡️ (a) Oxidation no. of S in S₈ is zero as free elements have zero oxidation number.
➡️ (b) Oxidation no. of S in SO₂Cl₂ is +6 [(+6) + 2(−2) + 2(−1) = 0] ⇒ [(+6) + (−4) + (−2) = 0] ✅
➡️ (c) Oxidation no. of S in Na₂S₄O₆ is +2.5 [2(+1) + 4(−2) + 6(−2) = 0 ⇒ (+2) + 4(+2.5) + (−12) = 0]
➡️ (d) Oxidation no. of S in Na₂S₂O₃ is +2 [2(+2) + 2(−2) + 3(−2) = 0] ⇒ [(+2) + 2(+2) + (−6) = 0]

24. The reaction, 2H₂O(l) → 4H⁺ (aq) + O₂ (g) + 4ē is a/an

a) Oxidation reaction

b) Reduction reaction

c) Hydrolysis reaction

d) Redox reaction

✅ Correct Answer: (a)
Since oxidation no. of O is increased from −2 to zero showing loss of two electrons, hence it is oxidation reaction.

25. The most common oxidation state of an element is −2. The number of electrons present in its outermost shell is:

a) 4

b) 6

c) 5

d) 2

✅ Correct Answer: (b)
The oxidation number of element −2 corresponds to the gain of two electrons showing that the element must contain 6 valence electrons.

26. Which one of the following formulae contains nitrogen with an oxidation state of +5?

a) NH₄⁺

b) N₂O₅

c) NO₂

d) N₂O

✅ Correct Answer: (b)
➡️ (a) Oxidation no. of N in NH₄⁺ is −3. [(−3) + 4(+1) = +1] ⇒ [(−3) + (+4) = +1]
➡️ (b) Oxidation no. of N in N₂O₅ is +5 [2(+5) + 5(−2) = 0] ⇒ [2(+5) + (−10) = 0] ✅ 👈
➡️ (c) Oxidation no. of N in NO₂ is +4 [(+4) + 2(−2) = 0] ⇒ [(+4) + (−4) = 0 ]
➡️ (d) Oxidation no. of N in N₂O is +1 [2(+1) + (−2) = 0]

27. The electronic configuration of an element is 1s², 2s² 2p⁵. In chemical reaction, it is most likely to

a) Donate 2 electrons

b) Gain one electron

c) Donate one electron

d) Gain 2 electrons

✅ Correct Answer: (b)
The electronic configuration of an element 1s², 2s² 2p⁵ shows that it contains 7 valence electrons lacking one electron to complete its octet.
Hence this element is most likely to gain one electron. 👈

28. What is the oxidation number associated of the element with oxygen in each of the following?
(i) CrO₄²⁻ (ii) ClO₄¹⁻ (iii) PO₄³⁻ (iv) PbO₂²⁻

a) +6, +7, +5, +2

b) +6, +5, +5, +4

c) +2, +5, +7, +6

d) +5, +6, +2, +7

✅ Correct Answer: (a)
The oxidation numbers associated of the element with oxygen are: +6, +7, +5, +2 → Option (a) 👈
➡️ (i). Oxidation no. of Cr in CrO₄²⁻ = +6 [(+6) + 4(−2) = −2] ⇒ [(+6) + (−8) = −2]
➡️ (ii). Oxidation no. of Cl in ClO₄¹⁻ = +7 [(+7) + 4(−2) = −1] ⇒ [(+7) + (−8) = −1]
➡️ (iii). Oxidation no. of P in PO₄³⁻ = +5 [(+5) + 4(−2) = −3] ⇒ [(+5) + (−8) = −3]
➡️ (iv). Oxidation no. of Pb in PbO₂²⁻ = +2 [(+2) + 2(−2) = −2] ⇒ [(+2) + (−4) = −2]

29. When Cl⁻ ions are converted to Cl₂, the oxidation number of chlorine increases from:

a) −1 to +1

b) −1 to zero

c) −1 to −2

d) −1 to +2

✅ Correct Answer: (b)
➡️Oxidation no. of Cl in Cl⁻ = −1
➡️Oxidation no. of Cl in Cl₂ = 0
➡️When Cl⁻ ions are converted to Cl₂, the oxidation number of chlorine increases from −1 (in Cl⁻) to zero (in Cl₂). 👈
➡️Cl⁻ → Cl₂ + 2ē (Reduction from −1 to zero). 👈

30. What is the oxidation number of Mn in the following compounds?
KMnO₄, Na₂MnO₄, MnO₂, MnCl₂

a) +7, +6, +4, +2

b) +7, +2, +6, +4

c) +6, +4, +7, +2

d) +7, +4, +6, +4

✅ Correct Answer: (a)
Oxidation numbers: +7, +6, +4, +2 → Option (a) ✅
➡️Oxidation no. of Mn in KMnO₄ (Potassium permanganate) = +1+ x + (−8) = 0 ⇒ x = +7 👉 Mn = +7
➡️Oxidation no. of Mn in Na₂MnO₄ (Sodium manganate) = +2 + x +(−8)= 0 ⇒ x = +6 👉 Mn = +6
➡️Oxidation no. of Mn in MnO₂(Manganese dioxide) = x+(−4)= 0 ⇒ x = +4 👉 Mn = +4
➡️Oxidation no. of Mn in, MnCl₂ (Manganese(II) chloride) = x +(−2) = 0 ⇒ x = +2 👉 Mn = +2

31. In which one of the following compounds does oxygen exhibit oxidation state of +1?

a) Na₂O₂

b) BaO₂

c) OF₂

d) O₂F₂

✅ Correct Answer: (d)
In O₂F₂, the oxidation number of O is +1.
Since F is the most electronegative element, its oxidation number is -1.

32. In which of the following formulae contains P in its highest oxidation state?

a) P₄

b) PH₃

c) PO₃³⁻

d) P₂O₇⁴⁻ (pyrophosphate)

✅ Correct Answer: (d)
Highest oxidation number is equal to group number of element.
Since P belongs to group VA of the periodic table, its highest oxidation number is +5 👈
➡️ (a) Oxidation no. of P in P₄ = 0 (free element shows zero oxidation state)
➡️ (b) Oxidation no. of P in PH₃ = −3
➡️ (c) Oxidation no. of P in PO₃³⁻ = +3
➡️ (d) Oxidation no. of P in P₂O₇⁴⁻ = +5✅ 👈

33. The difference of potential of two electrodes when concentration of solution is 1M each at 25°C and 1 atm is called

a) Cell voltage

b) Electrode potential

c) Cell reaction

d) Standard cell potential

✅ Correct Answer: (d)
The potential difference between two electrodes under standard conditions (concentration = 1 M, temperature = 25 °C, pressure = 1 atm) is called the standard cell potential (E°cell).

34. The overall positive value for the reaction potential predicts that process is energetically

a) Feasible

b) Not feasible

c) Impossible

d) Both b and c

✅ Correct Answer: (a)
Standard electrode potentials are widely used to predict the feasibility of redox processes.
In general if the electrode potential for the reaction is positive, it is regarded as being feasible.

35. The standard reduction potential of Zn is – 0.76V. The standard oxidation potential of Zn will be

a) +0.76V

b) >0.76V

c) <–0.76V

d) –0.76V

✅ Correct Answer: (d)
The standard reduction potential and standard oxidation potential of a metal is equal in magnitude but opposite in sign.
Hence the standard oxidation potential of zinc will be – 0.76V.

36. Standard reduction potential of three metals A, B and C are respectively +0.5 V, 3.0 V and – 1.2 V, their reducing power is

a) B > C > A

b) A > B > C

c) C > B > A

d) C > A > B

✅ Correct Answer: (d)
Correct option is d; C > A > B. The metal with least standard reduction electrode potential has the highest reducing power and vice-versa.
i.e. Higher the reduction potential lesser is reducing power and vice-versa.
More is the value of reduction potential, more is the tendency to get reduced, i.e. less is the reducing power
👉 Therefore, the order of the reducing power of these metals is C > A > B.
Higher the R.P., easier to reduce hence better O.A.
Thus species with higher reducing power (better R.A.) has a lower R.P.
➡️ C → E°₍red₎ = –1.2 V → Strongest reducing agent
➡️ A → E°₍red₎ = +0.5 V → Moderate reducing agent
➡️ B → E°₍red₎ = +3.0 V → Weakest reducing agent
📌 Key Point
As the standard reduction potential (E°₍red₎) increases, the reducing power decreases.

37. During electrolysis of 18 g of acidified water, H₂ released at cathode at s.t.p. is:

a) 22.4 liter

b) 11.2 liter

c) 5.6 liter

d) 44.8 liter

✅ Correct Answer: (a)
From the electrolytic decompsotion of water; 2H₂O → 2H₂ + O₂; 36 g of acidified water gives 44.8 liter of H₂ at STP.
Hence 18 g of acidified water will release 22.4 liter of H₂ gas at STP.

38. What ions are present in aqueous sodium sulphate solution?

a) Na⁺, SO₄²⁻ , H⁺, OH⁻

b) Na⁺, SO₄²⁻ , H⁺, O²⁻

c) Na²⁺, SO₃²⁻ , H⁺, O²⁻

d) Na²⁺, SO₄²⁻

✅ Correct Answer: (a)
Na₂SO₄ (aq) ⇌ 2Na⁺(aq) + SO₄²⁻⁺(aq)
H₂O(aq) ⇌ H⁺(aq) + OH⁻(aq)

39. Standard electrode potential of Zn²⁺/ Zn is

a) + 0.76 V

b) −0.76 V

c) −2.76 V

d) −1.66 V

✅ Correct Answer: (b)
Standard electrode potential of Zn²⁺/ Zn is −0.76 V

40. Standard electrode potential of Al/Al³⁺ is

a) +1.66 V

b) −1.66 V

c) + 0.66V

d) −0.66 V

✅ Correct Answer: (b)
Standard electrode potential of Al/Al³⁺ is −1.66 V.
The standard electrode potential is always quoted as reduction potential.

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کوئی حالت نہیں یہ حالت ہے یہ تو آشوب ناک صورت ہے انجمن میں یہ میری خاموشی بردباری نہیں ہے وحشت ہے تجھ سے یہ گاہ گاہ کا شکوہ جب تلک ہے بسا غنیمت ہے خواہشیں دل کا ساتھ چھوڑ گئیں یہ اذیت بڑی اذیت ہے لوگ مصروف جانتے ہیں مجھے یاں مرا غم ہی میری فرصت ہے طنز پیرایۂ تبسم میں اس تکلف کی کیا ضرورت ہے ہم نے دیکھا تو ہم نے یہ دیکھا جو نہیں ہے وہ خوبصورت ہے وار کرنے کو جاں نثار آئیں یہ تو ایثار ہے عنایت ہے گرم جوشی اور اس قدر کیا بات کیا تمہیں مجھ سے کچھ شکایت ہے اب نکل آؤ اپنے اندر سے گھر میں سامان کی ضرورت ہے آج کا دن بھی عیش سے گزرا سر سے پا تک بدن سلامت ہے جونؔ ایلیا