Home · NEET PYQs · Chemistry · Redox Reactions

NEET Redox Reactions PYQs with Solutions

421 previous year questions from Redox Reactions (NEET UG Chemistry) with answers and solutions. Numbered list, year tags, and one-tap solutions — built for serious JEE / NEET practice.

421 questionsChemistry2001–2026Answers + solutions

About Redox Reactions PYQs

Redox Reactions has 421 previous year questions in the Quantrex Academy NEET UG Chemistry bank. The 220 questions in this list come from NEET (186), AIIMS (18), MHT CET Medical (12) and 1 other source, spanning 2001 to 2026. Each question opens on its own page with the options, the correct answer and the worked solution where available.

NEET Redox Reactions PYQs with Solutions

About Redox Reactions PYQs

Questions by year (this list)

Redox Reactions questions with solutions

Calculate the oxidation number of sulfur in H_2SO_4 .

Consider the following compounds : K O_2, H_2 O _2 and H_2 S O_4 The oxidation state of the underlined elements in them are respectively,

What is the oxidation number of phosphorus in Mg_2P_2O_7 ?

Identify oxidant and reductant, respectively, in the following reaction: Zn(s) + Cu^ 2+ (aq) Zn^ 2+ (aq) + Cu(s)

Which of the following is true regarding oxidation?

In a reaction, 2H_2S + SO_2 arrow 2H_2O + 3S Identify the substance oxidized.

Predict the oxidation number of of 'C' in K_2C_2O_4 and in CH_2Cl_2 .

The oxidation process involves

The oxidation number of nitrogen in ammonia ( NH_3 ) is:

What is the change in oxidation number of S in the following reaction? SO_2 + 2H_2S arrow 3S + 2H_2O

Identify the gas that readily decolourises acidified KMnO_4 solution.

Find the average oxidation number of sulphur in tetrathionate ion.

Assertion : KMnO_4, KClO_4 , and HNO_3 act as oxidants. Reason : In KMnO_4, KClO_4 and HNO_3 central atom is in its highest oxidation state.

BrO_3^ - changes into Br_2 in an acidic medium of a unbalanced equation. How many electron should be present on the balanced equation?

When CH_3 COOCH_3+HCl is titrated with NaOH then at neutral point the colour of phenolphthalein becomes colourless from pink due to

Which of the following is disproportionation reaction?

When hydrogen peroxide is added to acidified solution of dichromate Cr_2 O_7^ 2- , a deep blue coloured complex of chromic peroxide CrO_5 is formed. Oxidation state of Cr in CrO_5

Assertion: Equivalent weight of NH_3 in the reaction, N_2 arrow NH_3 is 17 / 3 while that of N_2 is 28/6. Reason : Equivalent weight = Molecular weight array c Number of e^ - lost

How many Faradays are required to reduce 1 mol of BrO_3^ - to Br^ - .

Substances that are oxidised and reduced in the following reaction are respectively N_2 H_ 4(l) +2 H_2 O_ 2(l) N_ 2(g) +4 H_2 O_ (l)

Which of the following can be oxidised by SO_2 ?

For which of the following elements it is difficult to disproportionate in +3 oxidation state?

What is the oxidation number of Br in KBrO_4 ?

Assertion: The correct order of oxidising power is : VO_2^ + < Cr_2 O_7^ 2- < MnO_4^ - Reason: The oxidation state of Mn is +7 .

Which will not form precipitation after addition of (NH_4)_2 CO_3 in presence of NH_4 Cl ?

Predict the product of reaction of I_2 with H_2 O_2 in basic medium.

Assertion : Sulphur is oxidised by H_2 O_2 in presence of Fe (III). Reason : Fe (III) oxidises sulphur to sulphate.

Assertion : Chlorine undergoes disproportionation reaction in alkaline medium. Reason : Cl_2 is an oxidising agent.

Assertion : In an acid-base titration involving strong base and a weak acid, methyl orange can be used as an indicator. Reason : Methyl orange changes its colour in pH range of 7

2.5 ~g of the carbonate of a metal was treated with 100 ~mL of 1 ~N H_2 SO_4 . After the completion of the reaction, the solution was boiled off to expel CO_2 and was then

Assertion : In the iodometric titration starch is used as an indicator. Reason : Starch is a polysaccharide.

In the balanced chemical reaction IO_ 3 ^ - +a I^ - +b H^ + → c H _ 2 O+ d I_ 2 a, b, c and d respectively corresponds to

Oxidation state of Fe in Fe_3 O_4 is

Assertion : In some cases oxygen shows positive oxidation number though it is an electronegative element. Reason : Fluorine is more electronegative than oxygen.

Which element in the reaction of hydrogen peroxide (H 2 O 2 ) undergoes a change from an oxidation state of -1 to 0?

In which type of titration is K 2 Cr 2 O 7 used as a self-indicator?

In the reaction 2 Na(s) + H 2 (g) → 2 NaH(s), which element undergoes oxidation?

What is the purpose of thiosulfate ions (S 2 O 3 2-) in iodometry?

Why does iodine remain in solution when KI is present, forming KI 3 ?

Which element undergoes a change in oxidation state in this reaction 2 Na(s) + H 2 (g) → 2 NaH (s)?

In the half-reaction method for balancing chemical equations, what is added to balance O atoms in reactions occurring in acidic medium?

What is the process called when a species loses electrons?

In which form is Hg 2 (I)Cl 2 compared to Hg(II)Cl 2 ?

Which of the following is NOT a half reaction?

What is the term used to describe chemical reactions where oxidation and reduction occur simultaneously?

What is the purpose of using an indicator substance in a titration involving K 2 Cr 2 O 7 ?

Which substance is oxidized by K 2 Cr 2 O 7 to produce a dramatic blue color change?

Which chemical reaction involves the removal of electronegative element chlorine from ferric chloride?

What is the chemical symbol for an oxidizing agent in a redox reaction?

What is the term "oxidation" defined as in chemistry?

What does K 2 Cr 2 O 7 oxidize in the presence of diphenylamine to produce a blue color?

Which element is commonly used as an oxidizing agent in the extraction of metals from their ores?

In which type of solution is the addition of OH- ions necessary to balance ionic charges in a redox reaction?

What is the net balanced equation for the given redox reaction after canceling electrons on both sides?

Which of the following is an example of a reducing agent?

How many moles of electrons are transferred when 4 moles of sodium (Na) react completely 2 Na(s) + H 2 (g) → 2 NaH (s) ?

What happens to the oxidation state of an element when it acts as a reducing agent?

What type of chemical reaction involves the transfer of electrons from a reducing agent to an oxidizing agent?

In the reaction 2H 2 (g) + O 2 (g) → 2H 2 O(l), which element goes from a neutral (zero) state to a positive state?

What is the oxidation number of hydrogen when it is bonded to metals in binary compounds?

In the reaction 2H 2 (g) + O 2 (g) → 2H 2 O(l), what is the oxidation state of oxygen in H 2 O?

What is the purpose of adding H+ ions in a redox reaction carried out in acidic solution?

What is the color of K 2 Cr 2 O 7 before it undergoes reduction in a titration?

What is the purpose of stoichiometric calculations in iodometry?

What is the term used to describe the assumption of a complete transfer of electrons from a less electronegative atom to a more electronegative atom in chemical reactions?

What is the oxidation number of oxygen in superoxides?

What is the term used for the substance that causes oxidation in a redox reaction?

Which group in the periodic table exhibits the highest oxidation number equal to the group number?

Which term is used interchangeably with "oxidizing agent" and refers to a substance that accepts electrons in a chemical reaction?

What is the oxidizing agent in the given reaction, 2 Na (s) + H 2 (g) → 2 NaH (s)?

How is the oxidation number expressed in Stock notation?

Which element is oxidized in the reaction: 2 H 2 S(g) + O 2 (g) → 2 S (s) + 2 H 2 O (l)?

In a basic medium, what is added to the equation to balance each H+ ion?

In the oxidation number method for balancing redox reactions, what is the first step?

In which type of solution should OH- ions be added to balance ionic charges in a redox reaction?

When is the equation for a redox reaction considered balanced?