St Augustin Class 12 Chemistry Preselection Chemistry Paper 2023

St. Augustine’s Day School, Kolkata

Pre-selection Examination (2023-2024)

Class – XII Subject : Chemistry

Full Marks:- 70 ——————— Time : 3 hrs

Answers to this Paper must be written on the paper provided separately.

You will not be allowed to write during the first 15 minutes.

This time is to be spent in reading the question paper.

The time given at the head of this Paper is the time allowed for writing the answers.

SECTION – A (14 MARKS)

Question 1

(A) Fill in the blanks by choosing the appropriate words from those given in the brackets: [4×1] [depression, chemical, directly, sp³, electrical, heat, dsp², inversely, nitroalkane, elevation, alkyl nitrite]

1. A galvanic cell converts ____ energy into ____ energy
2. The ____ of the boiling point of solvent by a non-volatile solute is–proportional to the molality of the solution.
3. Square planar complex show ____ hybridization whereas tetrahedral complex shows ____ hybridisation
4. RNO₂ is called ____ and RONO is called ____.

(B) Select and write the correct alternative from the choices given below: [7 × 1]

(i) When zinc granule is dipped into copper sulphate solution, copper is precipitated because

1. both copper and zinc have a positive reduction potential
2. the reduction potential of copper is higher than that of zinc
3. the reduction potential of zinc is higher than that of copper
4. both zinc and copper have a negative reduction potential

(ii) For an octahedral complex, which of the following d-electron configurations will give maximum CFSE?

1. Hign spin, d⁶
2. Low spn, d⁵
3. Low spin, d⁴
4. High spin, d⁷

(iii) Toluene reacts with a halogen in the presence of iron(III) chloride giving ortho and para halo compounds. The
reaction is

1. electrophilic elimination reaction
2. free radical addition reaction
3. electrophilic substitution reaction
4. nucleophilic substitution reaction

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