Sub. code 3021
NEB — GRADE XII
Model Question
Class 12 Chemistry Model Question
The candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.
Pass Marks : 33
सबै प्रश्नको उत्तर दिनुहोस् । (Attempt All Questions)
This model question paper is for Class 12 Chemistry, (subject code 3021), carrying full marks of 75 with a pass mark of 33, to be completed within 3 Hours. Model answers are available for questions that have one — reveal them with a free account (a few reveals) or a paid plan (unlimited).
Group A
Rewrite the correct options of each question in your answer sheet.
Identify the equivalent weight of in the following reaction?
$49$
$294$
$98$
$108$
In a solution that is at equilibrium, what happens to the concentration of ions if the concentration of ions is increased?
The concentration of $\text{H}^+$ ions increases
The concentration of $\text{H}^+$ ions decreases
The concentration of $\text{H}^+$ ions stay the same
It depends on the initial concentration of ions
Assuming the rate of a reaction is doubled for every rise in temperature, how many times does the rate increase if temperature rises from $10^\circ\text{C}$ to ?
$112$ times
$400$ times
$512$ times
$614$ times
For the given reactions:
(i)
(ii)
The enthalpy of formation of becomes
$2y - x$
$2x - y$
$\dfrac{y - 2x}{2}$
What product would be obtained if red hot copper wire reacts with steam?
$\text{CuO}$
$\text{Cu}_2\text{O}$
$\text{Cu}_2\text{O}_2$
For which manufacturing process, Bessemer converter is used?
Pig iron
Steel
Wrought iron
Cast iron
When sodium phenoxide reacts with methyl bromide it gives
Cresol
Toluene
Benzene
Anisole
Identify the in the following reaction:
$\text{Na}_2\text{S}$
$\text{Sn}/\text{HCl}$
$\text{LiAlH}_4$
Which of the following reagents can be used to distinguish between a phenol and a carboxylic acid?
$\text{KOH}$
$\text{Na}$
$\text{NaOH}$
The colorless sweet smelling liquid compound A which exposed in air forms poisonous phosgene and also reacts with acetone gives sleep-inducing drug. Predict the product when the compound A reduced in a neutral medium?
Methylene chloride
Methane
Ethyne
Ethane
Oxygen containing organic compounds upon oxidation forms a carboxylic acid as the major organic product with its molecular mass higher by 14 units. Identify the organic compound.
A primary alcohol
An aldehyde
A ketone
A secondary alcohol
Group B
Write down the differences between rate of reaction and rate constant.
For the reaction $2A + B \rightarrow \text{product}$, following data were obtained:
order with respect to $A$ and $B$. $(1)$
the value of the rate constant of the reaction
the rate of reaction when the concentration of $A$ and $B$ is $0.5\ \text{M}$ and $0.4\ \text{M}$, respectively.
Four metals $A$, $B$, $C$ and $D$ react in the following way:
$B$ displaces only $A$ from solution. Only $D$ and $C$ displace hydrogen from $1\ \text{M HCl}$ solution. None of the metals will displace C from solution. Answer the followings:
Make the activity series of four metals with hydrogen
The standard potential for the following electrodes are:
Construct the galvanic cell by pointing out cathode and anode.
With $1\ \text{M}$ solution of the ions, what will be EMF of cell?
Will the reaction occur:
Occur? Give reasons. $(1)$
The addition of solution of required concentration in a reaction mixture yields profitable products and saves reactants.
A solution of HCl is labelled $2\ \text{M}$. Clarify its meaning?
In which aspects molarity is different from molality?
List the significance of normality factor in preparation of standard solution?
Liquor ammonia kept at a corner of your chemistry lab is $25%$ $(w/w)$ $\text{NH}_3$ and its specific gravity is $0.91$. Find the molarity of liquor ammonia.
An ammonia solution is added to the sulphate of coinage metal , the blue precipitates which appears dissolves in excess of reagent to form deep blue solution . Answer the followings:
Identify $A$, $B$ and $C$ with sequence of chemical reaction.
Predict the electronic configuration of this metal $A$.
Select the suitable methods for the purification of metal $A$.
What is meant by d-d electron transitions? List the characteristics of transition metals.
Write down the structural formula and IUPAC name of tertiary alcohol with formula . How would you apply Victor Meyer’s method for the distinction of 1-propanol and 2-propanol? Explain.
An organic compound X reacts with methyl magnesium bromide followed by acidic hydrolysis yields the compound $Y$. The compound Y on oxidation with acidified $\text{KMnO}_4$ yields $Z$. All three give positive iodoform test. Answer the followings:
Predict the compounds , and with sequence of reaction and give their IUPAC names.
Make the products by reacting with dilute ?
An organic compound when heated with acetone gives hypnotic and nervous sedative drugs and forms carbonyl chloride when it exposes to air.
Predict the organic compound $(X)$
Write the reactions for the formation of $(X)$ from ethanol.
Predict the new compound by treating $(X)$ with concentrated acid.
Convert $(X)$ into acetylene.
Nitro group in nitrobenzene is meta-directing group towards electrophilic substitution reaction, why? How does nitrobenzene react with?
$\text{Zn}/\text{NH}_4\text{Cl}$
$\text{LiAlH}_4$ $(2+2)$
What are the isomers of formula ?
Give an example of the following reactions
(a) Reimer–Tiemann’s reaction
(b) Perkin’s condensation reaction
(c) Williamson’s ether synthesis
(d) Cannizzaro’s reaction
(e) Sandmeyer’s reaction
Group C
The expressions of Ostwald’s dilution law is,
Derive it.
What information can you obtain from this expression?
Will strong electrolytes obey this expression, why?
$0.1\ \text{M}$ ethanoic acid is $1.34%$ ionized. Find its dissociation constant.
Hess's law is applied to calculate different types of enthalpy of reaction.
Illustrate the Hess law of constant heat summation.
Standard enthalpy of combustion of $\text{C (g)}$, $\text{H}_2\text{(g)}$ and $\text{C}_2\text{H}_2\text{(g)}$ are $-394\ \text{kJ mol}^{-1}$, $-286\ \text{kJ mol}^{-1}$ and $-1300\ \text{kJ mol}^{-1}$ respectively. Calculate enthalpy of formation of acetylene.
Draw the energy profile diagram of exothermic and endothermic reaction.
An organic compound has two functional isomers A and B. Isomer A changes blue litmus into red and B has fruity smell.
Give the reaction for the formation of $A$ by using Grignard's reagent.
Convert the isomer $A$ into isomer $B$?
Write a suitable test reaction to distinguish $A$ from methanoic acid.
Arrange the following in the decreasing order of their acidic strength and give reason for your answer:
$\text{CH}_3\text{COOH},\ \text{ClCH}_2\text{COOH},\ \text{FCH}_2\text{COOH}, \ \text{C}_6\text{H}_5\text{COOH}$ $(2)$
Amines are formally derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group which may respectively be called alkyl amines and aryl amines.
Give a test to distinguish alkyl amine and aryl amine.
How can you separate ethylamine and dimethylamine present in mixture by Hoffmann’s method?
Arrange the following amines in terms of increasing order of basic strength:
Propyl amine, ethyl methylamine, trimethylamine.
Convert: ethanamine to methanamine
How are cement classified on the basis of hardening and setting behavior?
Differentiate between
Paper and pulp
Artificial and natural radioactivity
Addition polymer and condensation polymer
Paper Overview & Analysis
Year
Model Question
Type
75
Full Marks
33
Pass Marks
3 Hours
Duration
56
Question Items
Question Type Breakdown
Group Breakdown
Chapter Breakdown
| Study of Heavy Metals | 3 items | 3 marks |
| Alcohols | 3 items | 9 marks |
| Thermodynamics | 2 items | 1 mark |
| Volumetric Analysis | 1 item | 1 mark |
| Ionic Equilibrium | 1 item | 1 mark |
| Chemical Kinetics | 1 item | 1 mark |
| Ethers | 1 item | 1 mark |
| Nitro Compounds | 1 item | 1 mark |
| Carboxylic Acid and its Derivatives | 1 item | 9 marks |
| Haloalkanes | 1 item | 1 mark |
| Transition Metals | 1 item | 5 marks |
| Aldehydes and Ketones | 1 item | 2 marks |
| Amines | 1 item | 1 mark |
| Cement | 1 item | 2 marks |
| Paper and Pulp | 1 item | 2 marks |
| Nuclear chemistry and application of radioactivity | 1 item | 2 marks |
| Chemistry in the Service of Mankind | 1 item | 2 marks |
Chapter breakdown covers 22 of 56 question items on this paper — the rest aren't tagged to a chapter yet.