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#### 12th Standard Chemistry English Medium Free Online Test One Mark Questions with Answer Key 2020 - Part Two

12th Standard EM

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Chemistry

Time : 00:25:00 Hrs
Total Marks : 25
25 x 1 = 25
1. Duralumin is an alloy of

(a)

Cu,Mn

(b)

Cu,Al,Mg

(c)

Al,Mn

(d)

Al,Cu,Mn,Mg

2. On hydrolysis, PCl3 gives

(a)

H3PO3

(b)

PH3

(c)

H3PO4

(d)

POCl3

3. Most easily liquefiable gas is

(a)

Ar

(b)

Ne

(c)

He

(d)

Kr

4. In acid medium, potassium permanganate oxidizes oxalic acid to

(a)

oxalate

(b)

Carbon dioxi

(c)

acetate

(d)

acetic acid

5. Which one of the following is not correct?

(a)

La(OH)2 is less basic than Lu(OH)3

(b)

In lanthanoid series ionic radius of Ln3+ ions decreases

(c)

La is actually an element of transition metal series rather than lanthanide series

(d)

Atomic radii of Zr and Hf are same because of lanthanide contract

6. Choose the correct statement

(a)

Square planar complexes are more stable than octahedral complexes

(b)

The spin only magnetic moment of [Cu(Cl)4]2- is BM and it has square planar structure.

(c)

Crystal field splitting energy $\left( { \Delta }_{ 0 } \right)$ [FeF6]4- is higher than the $(\Delta _{ 0 })$ $[Fe(CN)6]{ { 4 }^{ - } }$

(d)

crystal field stabilization energy of [V(H2O)6]2+ is higher than the crystal field stabilization of [Ti(H2O)6]2+

7. CsCl has bcc arrangement, its unit cell edge length is 400pm, its inter atomic distance is

(a)

400pm

(b)

800pm

(c)

$\sqrt { 3 } \times 100pm$

(d)

$\left( \cfrac { \sqrt { 3 } }{ 2 } \right) \times 400pm$

8. For a first order reaction A ⟶ product with initial concentration x mol L-1, has a half life period of 2.5 hours. For the same reaction with initial concentration $\left( \frac { x }{ 2 } \right)$ mol L-1 the half life is

(a)

(2.5 x 2) hours

(b)

$\left( \frac { 2.5 }{ 2 } \right)$hours

(c)

2.5 hours

(d)

Without knowing the rate constant, t1/2 cannot be determined from the given data

9. In a homogeneous reaction $A\longrightarrow B+C+D$ the initial pressure was P0 and after time t it was P. expression for rate constant in terms of P0, P and t will be

(a)

$k=\left( \cfrac { 2.303 }{ t } \right) log\left( \cfrac { 2{ P }_{ 0 } }{ { 3P }_{ 0 }-P } \right)$

(b)

$k=\left( \cfrac { 2.303 }{ t } \right) log\left( \cfrac { { 2P }_{ 0 } }{ { P }_{ 0 }-P } \right)$

(c)

$k=\left( \cfrac { 2.303 }{ t } \right) log\left( \cfrac { 3{ P }_{ 0 }-P }{ 2P_{ 0 } } \right)$

(d)

$k=\left( \cfrac { 2.303 }{ t } \right) log\left( \cfrac { 2{ P }_{ 0 } }{ { 3P }_{ 0 }-2P } \right)$

10. The solubility of BaSO4 in water is 2.42 ×10-3gL-1 at 298K. The value of its solubility product(Ksp) will be (Given molar mass of BaSO4 =233g mol 4-1)

(a)

1.08 ×10-14mol2L-2

(b)

1.08 ×10-12mol2L-2

(c)

1.08 ×10-10mol2L-2

(d)

1.08 ×10-8mol2L-2

11.  Electrolyte KCl KNO3 HCl NaOAC NaCl Λ- (Scm2 mol-1) 149.9 145.0 426.2 91.0 126.5

Calculate ΛoHoAC using appropriate molar conductances of the electrolytes listed above at infinite dilution in water at 25oC.

(a)

517.2

(b)

552.7

(c)

390.7

(d)

217.5

12. The equivalent conductance of M/36solution of a weak monobasic acid is 6mho cm2 and at infinite dilution is 400 mho cm2. The dissociation constant of this acid is

(a)

1.25 ×10−6

(b)

6.25 x 10-6

(c)

1.25 ×10−4

(d)

6.25 x 10 -5

13. On which of the following properties does the coagulating power of an ion depend ?

(a)

Both magnitude and sign of the charge on the ion.

(b)

Size of the ion alone

(c)

the magnitude of the charge on the ion alone

(d)

the sign of charge on the ion alone.

14. The correct IUPAC name of the compound,

(a)

4 – chloro – 2,3 – dimethyl pentan – 1-ol

(b)

2,3 – dimethyl – 4- chloropentan -1-ol

(c)

2,3,4 – trimethyl – 4- chlorobutan -1-ol

(d)

4– chloro – 2,3,4 – trimethyl pentan – 1-ol

15. Assertion : Phenol is more reactive than benzene towards electrophilic substitution reaction
Reason : In the case of phenol, the intermediate arenium ion is more stabilized by resonance

(a)

if both assertion and reason are true and reason is the correct explanation of assertion.

(b)

if both assertion and reason are true but reason is not the correct explanation of assertion.

(c)

assertion is true but reason is false

(d)

both assertion and reason are false.

16. Among the following ethers which one will produce methyl alcohol on treatment with hot HI?

(a)

(H3C)-3C-|-O-CH3

(b)

(CH3-)2-CH-CH2-O-CH3

(c)

CH3-(CH2)3-O-CH3

(d)

CH3-CH2-$\underset { \overset { | }{ { CH }_{ 3 } } }{ CH }$-O-CH3

17. The ionization constant of phenol is higher than that of ethanol because

(a)

phenoxide ion is bulkier than ethoxide

(b)

phenoxide ion is stronger base than ethoxide.

(c)

phenoxide ion is stablized through delocalisation.

(d)

phenoxide ion is less stable than ethoxide ion.

18. Compound of molecular formula C7H8O. is a sweet smeeling liquid. A on reaction with acidified K2Cr2O7 gives compound B of molecular formula C7H8O. B reduces Tollen's reagent A and B are respectively.

(a)

benzaldelyde and benzoic acid

(b)

Methyl phenykarbinol and acetophenone

(c)

benzyl alcohol and benzaldehyde

(d)

diphenyl carbinol and benzophenone

19. CH2=CH2+H2 The above reaction is _______

(a)

Lucas test

(b)

Saponification

(c)

Victor Meyer's test

(d)

hydroxylation

20. Ethers in the presence of atmospheric oxygen oxidises to give hydroperoxides and dialkyl peroxides Such a spontaneous reaction by atmospheric oxygen is called _________

(a)

auto oxidation

(b)

acylation

(c)

alkylation

(d)

dehydration

21. Formation of o and p - hydroxy benzaldehyde from phenol on treatment with CHCl3 and NaOH is _______

(a)

Riemer-Tiemann reaction

(b)

Kolbe's reaction

(c)

Coupling reaction

(d)

Hydrogenation

22. When phenol reacts with CCl4 and NaOH, the product formed is ________ acid.

(a)

salicylic

(b)

cinnamic

(c)

benzoic

(d)

carboxylic

23. The formation of cyanohydrin from acetone is an example of

(a)

nucleophilic substitution

(b)

electrophilic substitution

(c)

(d)

24. The IUPAC name of

(a)

but – 3- enoicacid

(b)

but – 1- ene-4-oic acid

(c)

but – 2- ene-1-oic acid

(d)

but -3-ene-1-oicacid

25. In aqueous solution of amino acids mostly exists in,

(a)

NH2-CH(R)-COOH

(b)

NH2-CH(R)-COO-

(c)

H3N+-CH(R)-COOH

(d)

H3N+-CH(R)-COO-