JEE Mains JEE Advance BITSAT
JEE Mains | PYQ

Year

All years 2026 2025 2024 2023 2022 2021

Consider the following reaction:
\( 2\mathrm{HSO_4^-}(aq) \xrightarrow[\text{(2) Hydrolysis}]{\text{(1) Electrolysis}} 2\mathrm{HSO_4^-} + 2\mathrm{H^+} + A \)
The dihedral angle in product \( A \) in its solid phase at \( 110 \, \text{K} \) is:

Which of the following options are correct for the reaction \( 2[\mathrm{Au}(\mathrm{CN})_2]^{-} \, (\mathrm{aq.}) + \mathrm{Zn}(s) \rightarrow 2\mathrm{Au}(s) + [\mathrm{Zn}(\mathrm{CN})_4]^{2-} (\mathrm{aq}) \)?

\( 200 \, \text{cc} \) of \( x \times 10^{-3} \, \text{M} \) potassium dichromate is required to oxidise \( 750 \, \text{cc} \) of \( 0.6 \, \text{M} \) Mohr’s salt solution in acidic medium. Here \( x = \) __________.

The reaction of \( \mathrm{H_2O_2} \) with potassium permanganate in acidic medium leads to the formation of mainly:

\( 500 \, \mathrm{mL} \) of \( 0.2 \, \mathrm{M} \) \( \mathrm{MnO_4^-} \) solution in basic medium when mixed with \( 500 \, \mathrm{mL} \) of \( 1.5 \, \mathrm{M} \) \( \mathrm{KI} \) solution, oxidises iodide ions to liberate molecular iodine. This liberated iodine is then titrated with a standard \( x \, \mathrm{M} \) thiosulphate solution in presence of starch till the end point. If \( 300 \, \mathrm{mL} \) of thiosulphate was consumed, then the value of \( x \) is ________.

Potassium dichromate acts as a strong oxidizing agent in acidic solution. During this process, the oxidation state changes from

\(20\,\text{mL}\) of \(0.02\,\text{M}\) \(\mathrm{K_2Cr_2O_7}\) solution is used for the titration of \(10\,\text{mL}\) of \(\mathrm{Fe^{2+}}\) solution in the acidic medium. The molarity of \(\mathrm{Fe^{2+}}\) solution is \(\_\_\_\_\_\_\) \(\times10^{-2}\,\text{M}\). (Nearest Integer).

When \( 10 \, \text{mL} \) of an aqueous solution of \( \mathrm{KMnO_4} \) was titrated in acidic medium, equal volume of \( 0.1 \, \text{M} \) of an aqueous solution of ferrous sulphate was required for complete discharge of colour. The strength of \( \mathrm{KMnO_4} \) in grams per litre is __________ \( \times 10^{-2} \). (Nearest integer)
[Atomic mass of \( \mathrm{K} = 39 \), \( \mathrm{Mn} = 55 \), \( \mathrm{O} = 16 \)]

Consider the following reduction processes:
\( \mathrm{Al^{3+}} + 3e^- \rightarrow \mathrm{Al(s)}, \ E^\circ = -1.66 \, \text{V} \)
\( \mathrm{Fe^{3+}} + e^- \rightarrow \mathrm{Fe^{2+}}, \ E^\circ = +0.77 \, \text{V} \)
\( \mathrm{Co^{3+}} + e^- \rightarrow \mathrm{Co^{2+}}, \ E^\circ = +1.81 \, \text{V} \)
\( \mathrm{Cr^{3+}} + 3e^- \rightarrow \mathrm{Cr(s)}, \ E^\circ = -0.74 \, \text{V} \)
The tendency to act as reducing agent decreases in the order:

$500\text{ mL}$ of $1.2\text{ M }\text{KI}$ solution is mixed with $500\text{ mL}$ of $0.2\text{ M }\text{KMnO}_4$ solution in basic medium. The liberated iodine was titrated with standard $0.1\text{M }\text{Na}_2\text{S}_2\text{O}_3$ solution in the presence of starch indicator till the blue color disappeared. The volume (in L) of $\text{Na}_2\text{S}_2\text{O}_3$ consumed is ______________. (Nearest integer)

Iron \( (\mathrm{III}) \) catalyses the reaction between iodide and persulphate ions, in which?
A. \( \mathrm{Fe^{3+}} \) oxidises the iodide ion
B. \( \mathrm{Fe^{3+}} \) oxidises the persulphate ion
C. \( \mathrm{Fe^{2+}} \) reduces the iodide ion
D. \( \mathrm{Fe^{2+}} \) reduces the persulphate ion
Choose the most appropriate answer from the options given below:

If \( 50 \, \text{mL} \) of \( 0.5 \, \text{M} \) oxalic acid is required to neutralise \( 25 \, \text{mL} \) of NaOH solution, the amount of NaOH in \( 50 \, \text{mL} \) of given NaOH solution is ___ \( \text{g} \).

Given below are two statements:
Statement (I) : Potassium hydrogen phthalate is primary standard for standardisation of sodium hydroxide solution.
Statement (II) : In this titration phenolphthalein can be used as indicator.
In the light of the above statements, choose the most appropriate answer from the options given below:

\( 2\mathrm{IO}_3^- + x\,\mathrm{I}^- + 12\mathrm{H}^+ \rightarrow 6\mathrm{I}_2 + 6\mathrm{H}_2\mathrm{O} \). What is the value of \( x \)?

Complete combustion of \( X \) g of an organic compound gave \( 0.25 \) g of \( \mathrm{CO_2} \) and \( 0.12 \) g of \( \mathrm{H_2O} \). If the \( \% \) of carbon is \( 25\% \) and of hydrogen is \( 4.89\% \), then \( X = \) ______ \( \times 10^{-3} \) g. (Nearest integer)

(Molar mass of \( \mathrm{C} \), \( \mathrm{H} \) and \( \mathrm{O} \) are \( 12 \), \( 1 \) and \( 16 \) g \( \mathrm{mol}^{-1} \) respectively.)

The covalency and oxidation state respectively of boron in \( \mathrm{[BF_4]^{-}} \), are:

Which of the given reactions is not an example of disproportionation reaction?

The oxidation state of manganese in the product obtained in a reaction of potassium permanganate and hydrogen peroxide in basic medium is_______.

In the titration of \( \mathrm{KMnO_4} \) and oxalic acid in acidic medium, the change in oxidation number of carbon at the end point is ______.

Metal deficiency defect is shown by \( \mathrm{Fe_{0.93}O} \). In the crystal, some \( \mathrm{Fe^{2+}} \) cations are missing and loss of positive charge is compensated by the presence of \( \mathrm{Fe^{3+}} \) ions. The percentage of \( \mathrm{Fe^{2+}} \) ions in the \( \mathrm{Fe_{0.93}O} \) crystals is __________ (Nearest integer)

The sum of oxidation state of the metals in \( \mathrm{Fe(CO)_5} \), \( \mathrm{VO^{2+}} \) and \( \mathrm{WO_3} \) is __________.

In order to oxidise a mixture of \( 1 \) mole each of \( \mathrm{FeC_2O_4} \), \( \mathrm{Fe_2(C_2O_4)_3} \), \( \mathrm{FeSO_4} \) and \( \mathrm{Fe_2(SO_4)_3} \) in acidic medium, the number of moles of \( \mathrm{KMnO_4} \) required is:

In basic medium, \( \text{H}_2\text{O}_2 \) exhibits which of the following reactions?
(A) \( \displaystyle \text{Mn}^{2+} \to \text{Mn}^{4+} \) (B) \( \text{I}_2 \rightarrow \text{I}^− \) (C) \( \text{PbS} \rightarrow \text{PbSO}_4 \)
Choose the most appropriate answer from the options given below:

Given below are two statements:
Statement I: In redox titration, the indicators used are sensitive to change in pH of the solutions
Statement II: In acid – base titration, the indicators used are sensitive to change in oxidation potential.
In the light of the above statements, choose the most appropriate answer from the Option given below

\( \mathrm{H_2O_2} \) acts as a reducing agent in.

\(0.01\,\text{M}\) KMnO\(_4\) solution was added to \(20.0\,\text{mL}\) of \(0.05\,\text{M}\) Mohr's salt solution through a burette. The initial reading of \(50\,\text{mL}\) burette is zero. The volume of KMnO\(_4\) solution left in the burette after the end point is ______ \( \text{mL} \). (nearest integer)

‘\( 25 \) volume’ hydrogen peroxide means

See the following chemical reaction:
\( \mathrm{Cr_2O_7^{2-}} + X\mathrm{H^+} + 6\mathrm{F_e^{2+}} \rightarrow Y\mathrm{Cr^{3+}} + 6\mathrm{F_e^{3+}} + Z\mathrm{H_2O} \)
The sum of \( X \), \( Y \) and \( Z \) is __________.

Which one of the following is an example of disproportionation reaction?

Given below are two statements:
Statement I: The correct order of electronegativity of fluorine, oxygen and nitrogen is \( \mathrm{F} > \mathrm{O} > \mathrm{N} \).
Statement II: The oxidation state of oxygen in \( \mathrm{OF_2} \) is \( +2 \) and in \( \mathrm{Na_2O} \) is \( -2 \).
In the light of the above statements, choose the correct answer from the options given below

Given below are two statements:
Statement I: In the oxalic acid vs \( \mathrm{KMnO_4} \) (in the presence of dil. \( \mathrm{H_2SO_4} \)) titration the solution needs to be heated initially to \( 60^\circ \mathrm{C} \), but no heating is required in Ferrous ammonium sulphate (FAS) vs \( \mathrm{KMnO_4} \) titration (in the presence of dil. \( \mathrm{H_2SO_4} \)).
Statement II: In oxalic acid vs \( \mathrm{KMnO_4} \) titration, the initial formation of \( \mathrm{MnSO_4} \) takes place at high temperature, which then acts as catalyst for further reaction. In the case of FAS vs \( \mathrm{KMnO_4} \), heating oxidizes \( \mathrm{Fe^{2+}} \) into \( \mathrm{Fe^{3+}} \) by oxygen of air and error may be introduced in the experiment.
In the light of the above statements, choose the correct answer from the options given below:

Which of the following cannot function as an oxidizing agent?

In Chromyl chloride, the oxidation state of chromium is (+) __________.

In acidic medium, \( \mathrm{K_2Cr_2O_7} \) shows oxidising action as represented in the half reaction:
$Cr_2O_7^{2-} + XH^+ + Ye^{\ominus} \rightarrow 2A + ZH_2O$
\( X \), \( Y \), \( Z \) and \( A \) respectively are:

Total number of species from the following which can undergo disproportionation reaction is _______.
\( \mathrm{H_2O_2,\ ClO_3^{-},\ P_4,\ Cl_2,\ Ag,\ Cu^{+1},\ F_2,\ NO_2,\ K^{+}} \)

From the given list, the number of compounds with +4 oxidation state of Sulphur is ___________ .
$\text{SO}_3$, $\text{H}_2\text{SO}_3$, $\text{SOCl}_2$, $\text{SF}_4$, $\text{BaSO}_4$, $\text{H}_2\text{S}_2\text{O}_7$

The number of electrons involved in the reduction permanganate to manganese dioxide in acidic medium is _______.

The lowest oxidation number of an atom in a compound \( \mathrm{A_2B} \) is \( -2 \). The number of electrons in its valence shell is _______.

The disproportionation of \( \mathrm{MnO_4^{2-}} \) in acidic medium resulted in the formation of two manganese compounds A and B. If the oxidation state of Mn in B is smaller than that of A, then the spin-only magnetic moment \( (\mu) \) value of B in \( \text{BM} \) is _______. (Nearest integer)

Which of the following reactions are disproportionation reactions?
(A) \( \text{Cu}^+ \rightarrow \text{Cu}^{2+} + \text{Cu} \)
(B) \( 3\text{MnO}_4^{2-} + 4\text{H}^+ \rightarrow 2\text{MnO}_4^- + \text{MnO}_2 + 2\text{H}_2\text{O} \)
(C) \( 2\text{KMnO}_4 \rightarrow \text{K}_2\text{MnO}_4 + \text{MnO}_2 + \text{O}_2 \)
(D) \( 2\text{MnO}_4^- + 3\text{Mn}^{2+} + 2\text{H}_2\text{O} \rightarrow 5\text{MnO}_2 + 4\text{H}^+ \)
Choose the correct answer from the options given below:

Only \( 2 \, \mathrm{mL} \) of \( \mathrm{KMnO}_4 \) solution of unknown molarity is required to reach the end point of a titration of \( 20 \, \mathrm{mL} \) of oxalic acid \( (2 \, \mathrm{M}) \) in acidic medium. The molarity of \( \mathrm{KMnO}_4 \) solution should be \( \_\_\_\_\_\_ \, \mathrm{M} \).

\( 20 \, \text{mL} \) of \( 0.02 \, \text{M} \) hypo solution is used for the titration of \( 10 \, \text{mL} \) of copper sulphate solution, in the presence of excess of \( \mathrm{KI} \) using starch as an indicator. The molarity of \( \mathrm{Cu^{2+}} \) is found to be be _______ \( \times 10^{-2} \, \text{M} \). (nearest integer)
Given : \( 2\mathrm{Cu^{2+}} + 4\mathrm{I^-} \rightarrow \mathrm{Cu_2I_2} + \mathrm{I_2} \)
\( \mathrm{I_2} + 2\mathrm{S_2O_3^{2-}} \rightarrow 2\mathrm{I^-} + \mathrm{S_2O_6^{2-}} \)

The standard electrode potential \( (\mathrm{M^{3+}} / \mathrm{M^{2+}}) \) for \( \mathrm{V} \), \( \mathrm{Cr} \), \( \mathrm{Mn} \) and \( \mathrm{Co} \) are \( -0.26 \ \mathrm{V} \), \( -0.41 \ \mathrm{V} \), \( +1.57 \ \mathrm{V} \) and \( +1.97 \ \mathrm{V} \), respectively. The metal ions which can liberate \( \mathrm{H_2} \) from a dilute acid are;

\( 10.0 \, \text{mL} \) of \( 0.05 \, \text{M} \; \mathrm{KMnO_4} \) solution was consumed in a titration with \( 10.0 \, \text{mL} \) of given oxalic acid dehydrate solution. The strength of given oxalic acid solution is _____ \( \times 10^{-2} \) \( \text{g} / \text{L} \) (Round off to the nearest Integer).

\( \mathrm{KMnO_4} \) is titrated with ferrous ammonium sulphate hexahydrate in presence of dilute \( \mathrm{H_2SO_4} \). Number of water molecules produced for \( 2 \) molecules of \( \mathrm{KMnO_4} \) is _______.

Chlorine undergoes disproportionation in alkaline medium as shown below:
\( a\mathrm{Cl_2}(g) + b\mathrm{OH^-}(aq) \rightarrow c\mathrm{ClO^-}(aq) + d\mathrm{Cl^-}(aq) + e\mathrm{H_2O}(l) \)
The values of \( a \), \( b \), \( c \) and \( d \) in a balanced redox reaction are respectively:

Identify the process in which change in the oxidation state is five:

Thiosulphate reacts differently with iodine and bromine in the reactions given below:
\( 2\mathrm{S_2O_3}^{2-} + \mathrm{I_2} \rightarrow \mathrm{S_4O_6}^{2-} + 2\mathrm{I^-} \)
\( \mathrm{S_2O_3}^{2-} + 5\mathrm{Br_2} + 5\mathrm{H_2O} \rightarrow 2\mathrm{SO_4}^{2-} + 4\mathrm{Br^-} + 10\mathrm{H^+} \)
Which of the following statement justifies the above dual behaviour of thiosulphate?

$2MnO_4^- + bI^- + cH_2O \rightarrow x I_2 + yMnO_2 + z\overline{O}H$
If the above equation is balanced with integer coefficients, the value of \( z \) is ________.

\( 15 \, \text{mL} \) of aqueous solution of \( \mathrm{Fe^{2+}} \) in acidic medium completely reacted with \( 20 \, \text{mL} \) of \( 0.03 \, \text{M} \) aqueous \( \mathrm{Cr_2O_7^{2-}} \). The molarity of the \( \mathrm{Fe^{2+}} \) solution is ______ \( \times 10^{-2} \, \text{M} \). (Round off to the Nearest Integer).

During the reaction of permanganate with thiosulphate, the change in oxidation of manganese occurs by value of \( 3 \). Identify which of the below medium will favour the reaction.

A \( 2.0 \, \text{g} \) sample containing \( \mathrm{MnO_2} \) is treated with \( \mathrm{HCl} \) liberating \( \mathrm{Cl_2} \). The \( \mathrm{Cl_2} \) gas is passed into a solution of \( \mathrm{KI} \) and \( 60.0 \, \text{mL} \) of \( 0.1 \, \text{M} \) \( \mathrm{Na_2S_2O_3} \) is required to titrate the liberated iodine. The percentage of \( \mathrm{MnO_2} \) in the sample is ______ (nearest integer) [Atomic masses (in \( \text{u} \)) \( \mathrm{Mn} = 55 \); \( \mathrm{Cl} = 35.5 \); \( \mathrm{O} = 16 \), \( \mathrm{I} = 127 \), \( \mathrm{Na} = 23 \), \( \mathrm{K} = 39 \), \( \mathrm{S} = 32 \)]

In neutral or alkaline solution, \( \mathrm{MnO}_4^{-} \) oxidises thiosulphate to:

In which one of the following sets all species show disproportionation reaction?

The species which does not undergo disproportionation reaction is:

The oxidation state of \( 'P' \) in \( \mathrm{H_4P_2O_7} \), \( \mathrm{H_4P_2O_5} \) and \( \mathrm{H_4P_2O_6} \) respectively, are:

Match the List-I with List-II.

Choose the correct answer from the options given below:

When \( 10 \, \mathrm{mL} \) of an aqueous solution of \( \mathrm{Fe^{2+}} \) ions was titrated in the presence of dil \( \mathrm{H_2SO_4} \) using diphenylamine indicator, \( 15 \, \mathrm{mL} \) of \( 0.02 \, \mathrm{M} \) solution of \( \mathrm{K_2Cr_2O_7} \) was required to get the end point. The molarity of the solution containing \( \mathrm{Fe^{2+}} \) ions is \( x \times 10^{-2} \, \mathrm{M} \). The value of \( x \) is ________. (Nearest integer)

← PreviousQuestion 2 of 58Next →

JEE Main 2023 6th April Morning Shift

Which of the following options are correct for the reaction \( 2[\mathrm{Au}(\mathrm{CN})_2]^{-} \, (\mathrm{aq.}) + \mathrm{Zn}(s) \rightarrow 2\mathrm{Au}(s) + [\mathrm{Zn}(\mathrm{CN})_4]^{2-} (\mathrm{aq}) \)?