Chemistry Specimen 2024: Sec-A ISC Sample Model Paper Solved

Chemistry Specimen 2024: Sec-A ISC Sample Model Paper Solved by expert teachers. Sample paper gives a blue print of upcoming exam. Therefore we have solved it according council latest guideline for 2024 exam. Visit official website CISCE for detail information about ISC Board Class-12.

Chemistry Specimen 2024: Sec-A ISC Sample Model Paper Solved

Board	ISC
Class	12th (xii)
Subject	Chemistry (Section-A)
Topic	ISC Specimen Paper Solved
Syllabus	on latest syllabus
Session	2023-24

ISC Class-12 Chemistry Specimen Paper 2024 Solved sec-A

Question 1 : (A) Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:

[ decreases, CN ion, activation energy, catalyst, two, Fe2+ ion, carbon, lattice energy, enzyme, five, double, halogen, triple, increases]

(i) In the Haber process, iron changes the __ of reaction while molybdenum increases the efficiency of the _,_.

(ii) The number of ions that will be produced when potassium ferrocyanide, K4[Fe(CN)6], dissolves in water is ...__. This shows that __ is the ligand in the coordination compound

(iii) Haloalkenes undergo both nucleophilic and electrophilic reactions due to the presence of ___bond and the _ atom.

(iv) In case of alcohols, as the carbon chain length increases, the boiling point ___ and the solubility in water__.

Answer :

(i) rate, catalyst

(ii) five, CN^– ion k4[Fc(CN)6]

(iii) double, halogen

(iv) Increase, decrease

(B) Select and write the correct alternative from the choices given below:

(i) A potassium iodide (KI) solution containing starch turns blue on the addition of chlorine. Which one of the following statements explain this?

(P) The reduction potential of Cl2 is more than that of I2.

(Q) The oxidation potential of Cl2 is more than that of I2.

(R) The product formed when Cl2 combines with starch is blue.

(S) The product formed when I2 combines with starch is blue.

(a) Only P and R

(b) Only Q and R

(c) Only Q and S

(d) Only P and S

Answer : (d) Only P and S

(ii) Crystal field splitting energy (CFSE) for high spin d4 octahedral complex is:

(a) -1·6 ∆o

(b) -1·2 ∆o

(c) -0·8 ∆o

(d) -0·6 ∆o

Answer : (d) -0·6 ∆o

(iii) Acidified K2Cr2O7 solution turns green when Na2SO3 is added to it. This is due to formation of:

(a) CrO4
(b) Cr2(SO3)3
(c) Cr2O3
(d) Cr2(SO4)3

Answer : (d) Cr₂(SO₄)₃

K₂CR₇ + 3H₂SO₄ + 3Na₂SO₃ → Cr₂(SO₄)₃ + K₂SO₄ + 3Na₂SO₄ + 4H₂0

(iv) Which of the following product is formed when benzene diazonium chloride is reduced by hypo phosphorous acid (H3PO2) in the presence of cuprous ion as catalyst?

(a) phenol

(b) Aniline

(c) Benzene

(d) Benzene cyanide

Answer : (c) Benzene

(v) Which of the following aqueous solution has lowest vapour pressure?

(a) 1M NaCl

(b) 1M K2SO4

(c) 1M Glucose

(d) 1M Sucrose

Answer : (b) 1M K₂SO₄

(vi) Assertion: Adding water to two beakers ‘A’ and ‘B’ containing NaOH and CH3COOH solutions respectively will increase the molar conductance (ꓥm) of the solutions sharply in beaker ‘A’ and slowly in beaker ‘B’.
Reason: Molar conductance (ꓥm) increases with a decrease in concentration or upon dilution.

(b) Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.
(c) Assertion is true but Reason is false.
(d) Assertion is false but Reason is true.

Answer : (b) Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.

(vii) Assertion: Aniline is soluble in HCl while it is only slightly soluble in water.
Reason: Aniline cannot make hydrogen bonds with water but gets protonated easily by acids.

(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.

(b) Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.

(c) Assertion is true but Reason is false.

(d) Assertion is false but Reason is true

Answer : (a) Both Assertion and Reason are true and Reason is the correctexplanation of Assertion

(C) Read the passage given below carefully and answer the questions that follow.

During the winter season in a particular year, Kashmir experienced heavy snowfall. It was an unexpected snowfall. Thousands of visitors were stranded because it was dangerous to travel on snowy roads and vehicles could not move as water froze in the car radiators. In such conditions officials decided to sprinkle rock salt or CaCl2 on roads.
(i) Why was it decided to sprinkle rock salt or CaCl2 on the roads?
(ii) A mixture of ethylene glycol and water is used as coolant in car radiators. Why?
(iii) How many grams of ethylene glycol (mol. wt. = 62 g mol-1
) should be added to 10 kg of water so that the solution freezes at -10oC? (Kf for water = 1ˑ86 K kg mol-1 )

Answer :

(i) Much lower freezing point of which is more effective at melting ICE.

(ii) Lowery the freezing point of water and used to cool the engine of car.

(iii) mm = 62 pg Mol-1, ω = 10 kg = 10000 g

Kf = 1.86 kg mol-1 , △Tf = 0° – (-10°) = 10°C

△Tf = Kf×ω× 1000/mm × W

10 = 1.86 × ω × 1000/62 × 10000

ω = 620000/1.66 , = 33333 g , = 3.33 kg

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