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Chemistry 11 Past Paper 2025 | Notely

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All Chemistry 11 papers

Class 11 · Past paper

Chemistry 11 past paper 2025

51 published questions in this index. The full practice view lets you work through them and track your own attempts.

16 MCQs35 written questionsPractise this paper

Question index

1
The third ionization potential value of an element is significantly high as compared to its 1st and 2nd ionization potentials. The element belongs to:
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1
Write down electronic configuration of: $_{29}Cu^{+2}$, $_{33}As$, $_{35}Br^{-1}$
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1
What is mass spectrometry? Explain the construction and working of a mass spectrometer. How can average atomic mass of an element be calculated from data obtained?
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2
Which pair of elements will most likely form an ionic bond?

This is a skimmable index, not a replacement for the study surface. Open the practice view to answer questions and use the linked study material.

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2

What is meant by **Catenation**? What is its importance in organic chemistry?

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2

Explain formation of covalent bonds in $O_2$ molecule on the basis of molecular orbital theory and valence bond theory. Justify that molecular orbital theory is superior to valence…

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3

Briefly explain the structure of $PCl_3$ and $NH_4^+$ ion on the basis of VSEPR theory.

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3

Describe by giving balanced chemical equations and necessary conditions that how a Carboxylic acid can be prepared from: a) $CH_3-CH_2-Cl$ b) $CH_3-CH_2-CH_2-OH$ c) $C_6H_5-CHO$

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4

The number of molecules present in $67.2\text{ dm}^3$ of $He$ gas at STP is:

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4

Write down the chemical tests with equations to identify chlorides, bromides and iodides present in aqueous solution.

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4

How can one identify the functional groups in the following compounds by chemical tests? Elaborate. a) $CH_3CHO$ b) $CH_3-CH_2-OH$ c) $CH_3-CH=CH_2$

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5

What will be the enthalpy of solution of $NaCl$ if $\Delta H$ (reverse lattice) is $+786\text{ kJ/mol}$ and $\Delta H$ (hyd) is $-783\text{ kJ/mol}$?

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5

Keeping in view the factors affecting bond energy, justify the order of bond energies in the following: a) Cl₂ > F₂ b) H₂ > HBr c) N₂ > O₂

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5

Why is Ethene more reactive than Ethane? Write down the reactions of Ethene with: a) $H_2SO_4 / H_2O$ b) $Cl_2 / H_2O$

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6

The following equilibrium will **NOT** be shifted in the forward direction by: ($N_2 + 3H_2 \rightleftharpoons 2NH_3 + \Delta$)

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6

Describe any three properties of water which are due to hydrogen bonding.

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6

What is solubility product? Derive an expression for the solubility product of $CaF_2$. How can the concept of solubility product be applied to predict the precipitation of $CaF_2$…

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7

Aqueous solution of which of the following salts will have pH less than 7?

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7

Write down three differences between limiting and non-limiting reactants.

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7

Explain the occurrence of a chemical reaction with reference to molecular collisions, activation energy, formation of activated complex and enthalpy changes in the reaction.

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8

Position of an element in periodic table with electronic configuration $1s^2, 2s^2p^6, 3s^2p^2$ is:

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8

Write down the reaction of Ethyl Bromide with $KOH_{(aq)}$, $NH_3$ and $AgNO_3$.

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9

Peroxyacetyl nitrate (PAN) is formed by the reaction of oxides of nitrogen with:

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9

State any three differences between crystalline and non-crystalline solids.

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10

Which of the following halides can reduce $H_2SO_4$ to $H_2S$?

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10

Briefly describe the terms 'shell', 'sub-shell' and 'orbital'.

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11

Identify the step in the mechanism of free radical chlorination of ethane: $CH_3-CH_3 + Cl^{\bullet} \longrightarrow CH_3-CH_2^{\bullet} + HCl$

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11

Why is the enthalpy of solution for $NH_4NO_3$ equal to $+25.7\text{ kJ/mol}$ (endothermic process) whereas that of $CaCl_2$ is $-83.0\text{ kJ/mol}$ (exothermic process)? Explain…

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12

Identify the product formed when Ethyl Bromide is warmed with $NaOH$ in ethanol:

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12

What is acid rain? Describe its formation with the help of chemical reactions involved.

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13

Which reagent is used for the reduction of Carboxylic acids to Alcohols?

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13

Write down any three measures that ensure the preservation of water resources.

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14

The compound which gives Silver mirror test as well as Iodoform test is:

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14

How can iodoform test be applied to the alcohols? Describe by giving chemical equations.

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15

Which pair of organic compounds can be distinguished by using 2,4-DNPH?

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15

Why aqueous solution of $Na_2CO_3$ is basic whereas that of $NH_4Cl$ is acidic? Justify by giving chemical equations.

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16

Identify correct relationship for determination of half-life of a first order reaction:

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16

How can ethylamine be prepared from: a) an alkyl halide b) a nitrite c) an amide

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17

Which of the following organic compound can be identified by Fehling solution test?

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17

Determine the principal energy level and number of valence electrons in the different sub-shells and orbitals of an element present in 3rd period and group-VIA of the periodic tabl…

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18

Write down the mechanism of base catalysed nucleophilic addition reaction of formaldehyde ($HCHO$) with $HCN$.

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19

Describe the use of compounds of sulphur in any three chemical industries.

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20

State Markovnikov's rule by giving an example and its mechanism.

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21

Calculate the volume occupied by $3.011 \times 10^{24}$ molecules of $NH_3$ gas enclosed in a container at STP.

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22

How is ethanol prepared from: a) Alkene b) Alkyl halide c) Carboxylic acid

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23

Briefly describe β-elimination reaction by giving a suitable example.

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24

Write down the reactions of 1-Propanol with: a) $SOCl_2$ b) $PCl_5$ c) Conc. $H_2SO_4$ / $180°C$

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25

Calculate $K_c$ for the following reaction at equilibrium at $100^{\circ}C$: $2SO_{2(g)} + O_{2(g)} \rightleftharpoons 2SO_{3(g)}$ $[SO_2] = 0.59\text{ M}, [O_2] = 0.05\text{ M}, […

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26

Calculate total entropy change when $NaCl$ dissolves in water under standard conditions: $NaCl_{(s)} \longrightarrow Na^+_{(aq)} + Cl^-_{(aq)}$ $S^{\circ}(NaCl) = 72.1\text{ J/mol/…

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27

Draw Born-Haber cycle for the formation of $KCl$. (Calculation is **NOT** required)

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28

For the reaction $N_2O_4 \longrightarrow 2NO_2$, the concentration of $N_2O_4$ is reduced from $0.1\text{ M}$ to $0.05\text{ M}$ in $60\text{ sec}$. If reaction is $1^{\text{st}}$…

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