Kerala Plus Two Answer Key 2022 Chemistry

ANSWER KEY

SECOND YEAR HIGHER SECONDARY EXAMINATION MARCH 2022
PART-I/II/III
SUBJECT: CHEMISTRY

CODE NO: SY 25 VERSION:
60 SCORES 2 HOURS

Qn. Sub Answer Key/Value Points Score Total
No. Qns Score
1 AgBr 1 1
2 Isotonic solutions 1 1
3 Kohlrausch law 1 1
4 s-1 or (b) 1 1
5 Emulsions or (a) 1 1
6 Froth Flotation or (d) 1 1
7 Sandmeyer Reaction or (b) 1 1
8 Lucas reagent/ Con.HCl & anhydrous ZnCl2 1 1
9 Fuel cells 1 1
10 2,4,6- tribromoaniline/ structure of 2,4,6- 1 1
tribromoaniline/ tribromoaniline
11 -CO-NH- or (c) 1 1
12 Bakelite or (a) 1 1
13 Aspartame/ any other given option 1 1

1

Qn. Sub Answer Key/Value Points Score Total
No. Qns Score
14 Correct explanation 2 2
(F-centres only- 1 score)
15 Statement/ correct equation 1 2
Any one application 1
16 (i) Correct equation(exponential/ logarithmic) 1

(ii)

2

1

Or
ԳՉ ԳՉ
slope = - Հ or - əşɚɗɚՀ

(Graph without marking slope - ½ score)
17 Definition 1 2
Any one consequence 1
18 Cr3+ d4 →d3 half filled t2g 1 2

Mn3+ d4 →d5 half filled d5 1
(stability due to half filled orbital - 1 score)
19 Explanation 1 2

Equation 1

2

20 +I effect of alkyl group / Electron releasing effect 1 2
of alkyl group

-R effect of aryl group / +R effect of -NH2 group /
Electron withdrawing effect of aryl group / +M
effect of -NH2 / conjugation of lone pair on nitrogen 1
with benzene ring / delocalisation of lone pair on
nitrogen with benzene ring / resonance effect / low
stability of anilinium ion

21 Any three differences 1+1+1 3

22

1
Or ΔTb = Kb x m
3
correct substitution
1

= 0.052
½

Tb = T0b + ΔT b/ 373.202 K
½

3

23 (i) Any two factors ½+½

(ii)
1
3

½

½

24 (i) CH3 -CH2 -Br + NaI→ CH3 -CH2 -I + NaBr / 1
Finkelstein reaction/ any other correct method
3
(ii) SN1 1

First order kinetics / takes place in two steps /
carbocation intermediate / racemisation / correct
mechanism 1
25 (i) R-MgX / Alkyl magnesium halides/ suitable 1
example
3
(ii) statement 1

example 1
26 (i) Intermolecular H bonding/ H bonding 1

(ii) Acetylsalicylic acid/ 2-acetoxybenzoic acid/ 1 3
structure of aspirin/ analgesic/ pain killer

correct equation/ acetylation of salicylic acid 1

4

27 (i)

or name + CH3I or name ½+½

3
(ii) Definition/ explanation 1

example 1
28 (i) Definition 1

(ii) Electrode reactions 1+1 4

Total cell reaction 1
29 (i) Correct distinction 1+1

(ii) Definition 1 4

Anyone application - ultramicroscope 1
30 (i) 3 steps involved in leaching (equation/ explanation) 1+1+1
4

(ii) Correct reason 1
31 (i) Definition 1

Example 1
4
(ii) Definition / animal starch 1

(iii) Amylose and amylopectin/ polymer of ⍺- glucose ½+½

5

32 (i) Two differences/ one difference and example of 1+1
each type
4
(ii) chloroprene/ 2-Chlorobuta-1,3-diene 1

1

33 (i) Definition/ explanation of each 1+1
4
examples of each ½+½

(ii) BHT/ BHA/ suitable examples 1
34 (i) PCl5 → PCl3 + Cl2 1

(ii) Definition 1
6
Any two examples/ any two types ½+½

(iii) Correct 3 steps 1+1+1

35 (i) Figure of two geometrical isomers 1+1

(ii) Four types of structural isomerism/ 6
Explanation of suitable example of each isomer 4
36 (i) H-COONa or name + CH3-OH or name 1+1

(ii) Correct explanation/ equation 2
6
(iii) Any correct reagents and condition
[CrO2Cl2, NaOH/Δ or CrO2Cl2, H3O+/Δ] / [CrO3, 2
(CH3CO)2O, NaOH/Δ or CrO3,(CH3CO)2O,
H3O+/Δ)] /[Cl2/hᶟ, NaOH/Δor Cl2/hᶟ, H3O+/Δ]/
Name of reaction

6