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A “good fit” is considered to be one where the cation can touch:  (a) all of its nearest neighbour anions.  (b) most of its nearest neighbour anions.  (c) some of its nearest neighbour anions.  (d) none of its nearest neighbour anions. SOLUTION (a) all of its nearest neighbour anions.  Explanation: A “good fit” is considered to be one where the cation can touch:   all of its nearest neighbour anions.  51 52 53 54 55 CBSE Class 12 Chemistry Sample Paper-2021-22

A solid AB has square planar structure. If the radius of cation A+ is 120pm, calculate the maximum possible value of anion B-  (a)240 pm  (b)270 pm  (c)280 pm  (d)290 pm   SOLUTION (d)290 pm Explanation: Square Planner means ratio between 0.414 - 0.732 If radius of caption is 120 pm then anion should be in the rang ρ = rcation/ranion 0.414 = 120/ x so x = 289.8 = 290 pm 0.732 = 120/ x so x = 163.9 = 164 pm 51 52 53 54 55 CBSE Class 12 Chemistry Sample Paper-2021-22

The radius of Ag+ ion is 126pm and of I- ion is 216pm. The coordination number of Ag+ ion is:  (a)2  (b)3  (c)6  (d)8   SOLUTION (c)6  Explanation: The radius of Ag+ ion is 126pm and of I- ion is 216pm.  The coordination number of Ag+ ion is ρ = r{caton/ranion} = r{caton/ranion} = `126/261` = 0.58 The radius ratio is in the range 0.414 - 0.732, so the coordinate number is 6 or 4 according to the table. Since none of the options is 4. so, the answer is 6.  51 52 53 54 55 CBSE Class 12 Chemistry Sample Paper-2021-22

Complete the following analogy: Same molecular formula but different structures:  A:: Non superimposable mirror images: B  (a) A:Isomers B: Enantiomer  (b) A: Enantiomers B: Racemic mixture  (c) A: Sterioisomers B: Retention  (d) A: IsomersB: Sterioisomers  SOLUTION (a) A:Isomers B: Enantiomer  50 51 52 53 54 CBSE Class 12 Chemistry Sample Paper-2021-22

Which of the following analogies is correct:  (a)Nitrogen: 1`"s"^{2}` 2`"s"^{2}` 2`"p"^{3}` :: Argon:1`"s"^{2}` 2`"s"^{2}` 2`"p"^{6}`  (b)Carbon: maximum compounds :: Xenon: no compounds  (c) `"XeF"_{2}`: Linear :: `"ClF"_{3}`: Trigonal planar  (d)Helium: meteorological observations:: Argon: metallurgical processes   SOLUTION (d)Helium: meteorological observations:: Argon: metallurgical processes 49 50 51 52 53 CBSE Class 12 Chemistry Sample Paper-2021-22

  Match the following: I II (i)Amino acids (A)protein (ii)Thymine (B)Nucleic acid (iii)Insulin ( C)DNA (iv)phosphodiester linkage (D)Zwitter ion (v) Uracil v Which of the following is the best matched options?  (a) i-A, v- D, iii- C, iv-B  (b) i-D, ii-C, iii- A, iv-B  (c) i-D, v- D, iii- A, iv-B  (d) i-A, ii- C, iii- D, iv-B SOLUTION (b) i-D, ii-C, iii- A, iv-B  Explanation: Amino acids form proteins and exist as zwitter ion , Thymine is a nitrogenous base in DNA, Insulin is a protein , phosphodiester linkage is found in nucleic acids so also in DNA and Uracil is nitrogenous base found in RNA which is a nucleic acid. 48 49 50 51 52 CBSE Class 12 Chemistry Sample Paper-2021-22

Given below are two statements labelled as Assertion (A) and Reason (R)  Assertion (A): Cryoscopic constant depends on nature of solvent.  Reason(R ): Cryoscopic constant is a universal constant. Select the most appropriate answer from the options given below:  (a) Both A and R are true and R is the correct explanation of A  (b) Both A and R are true but R is not the correct explanation of A.  (c)A is true but R is false.  (d) A is false but R is true.   SOLUTION (c)A is true but R is false.  47 48 49 50 51 CBSE Class 12 Chemistry Sample Paper-2021-22

Given below are two statements labelled as Assertion (A) and Reason (R)  Assertion(A): SO2 is reducing while TeO2 is an oxidising agent.  Reason(R): Reducing property of dioxide decreases from SO2 to TeO2. Select the most appropriate answer from the options given below:  (a) Both A and R are true and R is the correct explanation of A  (b) Both A and R are true but R is not the correct explanation of A.  (c)A is true but R is false.  (d) A is false but R is true.   SOLUTION (a) Both A and R are true and R is the correct explanation of A  46 47 48 49 50 CBSE Class 12 Chemistry Sample Paper-2021-22

Given below are two statements labelled as Assertion (A) and Reason (R)  Assertion(A):  Molarity of a solution changes with temperature. Reason (R):  Molarity is a colligative property. Select the most appropriate answer from the options given below:  (a) Both A and R are true and R is the correct explanation of A  (b) Both A and R are true but R is not the correct explanation of A.  (c)A is true but R is false.  (d) A is false but R is true.   SOLUTION (c)A is true but R is false.  45 46 47 48 49 CBSE Class 12 Chemistry Sample Paper-2021-22

Given below are two statements labelled as Assertion (A) and Reason (R)  Assertion (A):  Alkyl halides are insoluble in water.  Reason (R):  Alkyl halides have halogen attached to sp3 hybrid carbon. Select the most appropriate answer from the options given below:  (a) Both A and R are true and R is the correct explanation of A  (b) Both A and R are true but R is not the correct explanation of A.  (c)A is true but R is false.  (d) A is false but R is true. SOLUTION (b) Both A and R are true but R is not the correct explanation of A.  44 45 46 47 48 CBSE Class 12 Chemistry Sample Paper-2021-22

Given below are two statements labelled as Assertion (A) and Reason (R)  Assertion (A):  Electron gain enthalpy of oxygen is less than that of Flourine but greater than Nitrogen.  Reason (R):  Ionisation enthalpies of the elements follow the order Nitrogen > Oxygen > Fluorine   Select the most appropriate answer from the options given below:  (a) Both A and R are true and R is the correct explanation of A  (b) Both A and R are true but R is not the correct explanation of A.  (c) A is true but R is false.  (d) A is false but R is true. SOLUTION (c) A is true but R is false.  43 44 45 46 47 CBSE Class 12 Chemistry Sample Paper-2021-22

Alkenes decolourise bromine water in presence of CCl4 due to formation of:  (a) allyl bromide  (b) vinyl bromide  (c) bromoform  (d) vicinal dibromide SOLUTION (d) vicinal dibromide Explanation: Alkenes decolourise bromine water in presence of CCl4 due to formation of vicinal dibromide. 42 43 44 45 46 CBSE Class 12 Chemistry Sample Paper-2021-22

Identify the secondary alcohols from the following set:  (i)`"CH"_{3}` `"CH"_{2}`CH(OH)`"CH"_{3}`  (ii) (C2H5)3COH  (iii) (a)(i) and (iv)  (b)(i) and (iii)  (c)(i) and (ii)  (d)(i), (iii) and (iv) SOLUTION (a)(i) and (iv)  41 42 43 44 45 CBSE Class 12 Chemistry Sample Paper-2021-22

Which of the following statements is true:  (a) Ammonia is the weakest reducing agent and the strongest base among Group 15 hydrides.  (b) Ammonia is the strongest reducing agent as well as the strongest base among Group 15 hydrides.  (c) Ammonia is the strongest reducing agent as well as the weakest base among Group 15  (d) Ammonia is the strongest reducing agent and the weakest base among Group 15 hydrides. SOLUTION (a) Ammonia is the weakest reducing agent and the strongest base among Group 15 hydrides.  40 41 42 43 44 CBSE Class 12 Chemistry Sample Paper-2021-22

o-hydroxy benzyl alcohol when reacted with PCl3 gives the product as (IUPAC name)  (a) o- hydroxy benzyl chloride  (b) 2- chloromethylphenol  (c) o-chloromethylchlorobenzene  (d) 4-hydroxymethylphenol   SOLUTION (b) 2- chloromethylphenol  Explanation: 39 40 41 42 43 CBSE Class 12 Chemistry Sample Paper-2021-22

What would be the reactant and reagent used to obtain 2,. 4-dimethyl pentan-3-oI?  (a) Propanal and propyl magnesium bromide  (b) 3-methylbutanal and 2-methyl magnesium  (c) 2-dimethylpropanone and methyl magnesium iodide  (d) 2- methylpropanal and isopropyl magnesium iodide SOLUTION (d) 2- methylpropanal and isopropyl magnesium iodide Explanation: 38 39 40 41 42 CBSE Class 12 Chemistry Sample Paper-2021-22

Which one of the following are correctly arranged on the basis of the property indicated: (a)`"l"_{2}`< `"Br"_{2}`<`"F"_{2}`<`"Cl"_{2}`[ increasing bond dissociation enthalpy] (b) `"H"_{2}"O"` > `"H"_{2}"S"`<`"H"_{2}"Te"` <`"H"_{2}"Se"` [ increasing acidic strength] (c) `"NH"_{3}` < `"N"_{2}"O"`< `"NH"_{2}"OH"` <`"N"_{2}``"O"_{5}` [ increasing oxidation state] (d)`"BiH"_{3}`<`"SbH"_{3}`<`"AsH"_{3}`<`"PH"_{3}`<`"NH"_{3}` [ increasing bondangle] SOLUTION (d)`"BiH"_{3}`<`"SbH"_{3}`<`"AsH"_{3}`<`"PH"_{3}`<`"NH"_{3}` [ increasing bondangle] 37 38 39 40 41 CBSE Class 1

A unit cell of NaCl has 4 formula units. Its edge length is 0.50 nm. Calculate the density if molar mass of NaCl = 58.5 g/mol.  (a) 1 g/ `"cm"^{3}` (b) 2 g/ `"cm"^{3}` (c) 3 g/ `"cm"^{3}` (d) 4 g/ `"cm"^{3}` SOLUTION (c) 3 g/ `"cm"^{3}` Explanation: We Know that,  Density = `\frac{("Z"\times "m")}{("a"^{3}\times "Na")}` Density = `\frac{(4\times 58.8)}{(0.5\times 10^{-7})\times 6.023 \times 10^{23}}` Density = 3 g/`"cm"^{3}` 36 37 38 39 40 CBSE Class 12 Chemistry Sample Paper-2021-22

In lake test for `Al^{3}`+ ions, there is the formation of coloured ‘floating lake’. It is due to: (a)Absorption of litmus by [`"Al(OH)"_{4}`] - (b)Absorption of litmus by `"Al(OH)"_{3}` (c)Adsorption of litmus by [`"Al(OH)"_{4}`] - (d) Adsorption of litmus by `"Al(OH)"_{4}` SOLUTION (d) Adsorption of litmus by `"Al(OH)"_{4}` Explanation: In lake test for `Al^{3}`+ ions, there is the formation of coloured ‘floating lake’ In lake test for `Al^{3}`+ ions, there is the formation of coloured ‘floating lake’ due to adsorption. 35 36 37 38 39 CBSE Class 12 Chemistry Sample Paper-2021-22

In the following reaction,identify A and B (a) A= COOH-`("CH"_{2})_{4}` -COOH, B= OHC-(CHOCO`"CH"_{3})_{4}` -`"CH"_{2}`OCO`"CH"_{3}` (b) A= COOH-`("CH"_{2})_{4}` -CHO , B= OHC-(CHOCO`"CH"_{3})_{4}` -`"CH"_{2}`OCO`"CH"_{3}` (c) A= OHC-(CHOCOC`"H"_{3})_{3}`-C`"H"_{2}`OCOC`"H"_{3}` B= COOH-`"(CH"_{2})_{4}` -CHO , (d) A= OHC-(CHOCOC`"H"_{3})_{4}`-`"CH"_{2}`OCOC`"H"_{3}` B= `"COOH-(CH"_{2})_{4}` -COOH SOLUTION (d) A= OHC-(CHOCOC`"H"_{3})_{4}`-`"CH"_{2}`OCOC`"H"_{3}` B= `"COOH-(CH"_{2})_{4}` -COOH 34 35 36 37 38 CBSE Class 12 Chemistry Sample Paper-2021-22

Water retention or puffiness due to high salt intake occurs due to:  (a)diffusion  (b)vapour pressure difference  (c) osmosis  (d)reverse osmosis SOLUTION (c) osmosis  Explanation: Water retention or puffiness due to high salt intake occurs due to osmosis. 33 34 35 36 37 CBSE Class 12 Chemistry Sample Paper-2021-22

Ozone is a/ an __________ molecule and the two O-O bond lengths in ozone are (i)_______-and (ii) ____________  (a) linear ,110pm ; 148pm  (b) angular, 110pm ; 148pm  (c)linear, 128pm ; 128pm  (d)angular, 128pm ; 128pm   SOLUTION (d) angular, 128pm ; 128pm Explanation: Ozone is a resonance hybrid of two equivalent structures Ozone is a/ an angular molecule and the two O-O bond lengths in ozone are (i) 128pm ; -and (ii) 128pm 32 33 34 35 36 CBSE Class 12 Chemistry Sample Paper-2021-22

The reaction of toluene with C`"l"_{2}` in presence of FeC`"l"_{3}` gives ‘X’ while theof toluene with C`"l"_{2}` in presence of light gives ‘Y’. Thus ‘X’ and ‘Y’are:  (a) X = benzyl chloride Y = o and p – chlorotoluene  (b) X = m – chlorotoluene Y = p – chlorotoluene  (c) X = o and p–chlorotoluene Y = trichloromethylbenzene  (d) X= benzyl chloride, Y = m-chlorotoluene   SOLUTION (c) X = o and p–chlorotoluene Y = trichloromethylbenzene  31 32 33 34 35 CBSE Class 12 Chemistry Sample Paper-2021-22