Sub. code 3021
NEB — GRADE XII
2080
Old Question
Chemistry Question Paper 2080 (Old 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 : 32
सबै प्रश्नको उत्तर दिनुहोस् । (Attempt All Questions)
This old question question paper is for Class 12 Chemistry, 2080 (subject code 3021), carrying full marks of 75 with a pass mark of 32, to be completed within 3hrs. Answers with step-by-step solutions are available for every question below.
Group A
Rewrite the correct answer of each question in your answer sheet
An aqueous solution having pH = 10 is:
acidic
basic
amphoteric
neutral
The rate constant of a reaction is 21 × 10⁻² mol² litre⁻² min⁻¹. The order of the reaction is:
zero
first
second
third
For a reaction:
2SO₂(g) + O₂(g) → 2SO₃(g)
The entropy:
increases
decreases
remains unchanged
unpredictable
CaSO₄ is most soluble in minimum bulk because:
Ca²⁺ gets oxidised
Ca²⁺ gets reduced
CaSO₄ ionises
CaSO₄ gets decomposed
Carbolic acid is:
phenol
methanol
formic acid
acetic acid
CH₃CH₂Cl (X) (Y) In this reaction, the compound (Y) is:
primary amine
secondary amine
tertiary amine
2-amino propane
Dacron is prepared commercially by:
Dow's process
Dacron's process
Raschig process
Elbert's process
Which of the following compound gives iodoform test?
Propanone
Propanal
Butanal
Pentanal
The colourless liquid (A) reacts with sodium metal at room temperature to produce sodium salt of carboxylic acid and ammonia. Identify liquid compound (A).
Formamide
Propanamide
Acetamide
Methyl ethanoate
Galvanization is:
immersing the process
electroplating
tinning the process
electrifying
Brass contains:
Cu as deposit
alloy of Cu
pure Cu
Cu containing 1% impurity
Group B
short answer question
You are given a bottle containing a mixture of primary, secondary and tertiary amine. Apply Hofmann's method to separate each amine from its pure system.
Perform the following conversions:
i) Benzene → Cyclohexane
ii) Benzene → Nitrobenzene
iii) Cumene → Phenol
iv) Aldol → Crotonaldehyde
v) Ethanal → Lactic acid
An organic compound (M) (C₄H₈O₂) undergoes acid hydrolysis to give a carboxylic acid (N) and an alcohol (P). The alcohol (P) is oxidised with KMnO₄/H⁺ to give the carboxylic acid (N).
Draw the structural formula of (M), (N) and (P).
What product will you obtain when (M) is reduced in LiAlH₄?
Vinegar is an aqueous solution of acetic acid containing about 5 to 8% by volume in the aqueous solution.
Give any three methods of preparation of acetic acid.
Convert acetic acid into acetyl anhydride.
Mention an important use of vinegar.
Write down the chemistry of blue-vitriol.
A metal (M) having atomic number 30 is referred as non-typical transition metal and it belongs with the group IIB.
Identify the metal (M) and write its chief ore.
Why (M) is called non-typical transition metal?
Write the chemical process occurring in reduction step during the extraction of (M).
An electrochemical cell is constructed by using Zn electrode and Pb electrode whose standard electrode potential values are −0.76 V and −0.13 V respectively.
Indicate anode and cathode.
Write an electrochemical cell notation.
Write down the redox cell reactions.
Calculate the emf of the cell
Solubility product principle and common ion effect are simultaneously applied in qualitative salt analysis.
Distinguish between solubility product principle and common ion effect.
Apply solubility product principle and common ion effect in salt analysis of group III B metal ions.
Define heat of formation. Calculate the heat of formation of acetic acid from the following data:
C(s) + O₂(g) → CO₂(g), ΔH = −99 Kcal/mol
H₂(g) + ½O₂(g) → H₂O(l), ΔH = −68 Kcal/mol
CH₃COOH(l) + 2O₂(g) → 2CO₂(g) + 2H₂O(l), ΔH = −208 Kcal/mol
Represent a regular sequence of chemical reactions of the following sets of organic compounds using suitable reagents, catalysts or conditions with proper reasons.
CH₃COOH, CH₃Br, CH₃COOMgBr, CH₃MgBr.
Group C
long answer question
Normality and molarity are the terminologies of volumetric analysis used to express the concentration of solution.
Distinguish between molarity and normality
Deduce the normality equation S₁V₁ = S₂V₂.
Why is this equation not always used to calculate molarity?
Your chemistry teacher added 4 gm of sodium hydroxide in a bottle containing 20 CC of 2N H₂SO₄ and diluted it up to 1 litre by adding water. Then, he gave you a blue and a red litmus paper.
Which litmus paper would you use to test the solution and why?
Calculate the normality of the dilute solution
In the following given reaction:
SO₃ + 3H₂S → 3H₂O + 4S
Express the rate of above reaction in terms of reactants and products.
The concentration of H₂S decreased by 0.06 mol/litre in 2 seconds.
Calculate the rate of formation of Sulphur.
Why is rate of formation of water not equal to the rate of disappearance of SO₃?
Calculate the rate of disappearance of SO₃.
Draw an energy profile diagram to illustrate the effect of catalyst on the activation energy hence on rate.
Define energy of activation.
An alcohol (P) having molecular formula C₄H₁₀O undergoes Victor-Meyer's test to give blue colour at the end of reaction when added KOH solution.
Draw structural formula and write IUPAC name of (P).
Write down complete chemical reaction for the Victor-Meyer test of (P).
How would you prepare (P), starting from CH₃MgBr?
What product would you obtain when P is oxidized?
Convert propan-1-ol into propan-2-ol.
Give correct chemical reaction for the preparation of chlorobenzene from:
a) benzene
b) benzene diazonium chloride
Why is haloarene less reactive than haloalkane towards nucleophilic substitution reactions?
A reaction sequence is given below:
Write down the reagents and conditions for (P) and (Q).
Draw structural formula of (R) and (S).
Write short note of pulp and paper industry in Nepal.
Give structural formula of monomers and one use of each polymer:
Polythene
Teflon
Bakelite
Polystyrene
Paper Overview & Analysis
2080
Year
Old Question
Type
75
Full Marks
32
Pass Marks
3hrs
Duration
55
Question Items
Question Type Breakdown
Group Breakdown