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

12th Standard EM

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Chemistry

Time : 00:25:00 Hrs
Total Marks : 25
25 x 1 = 25
1. In the electrolytic refining of copper, which one of the following is used as anode?

(a)

Pure copper

(b)

Impure copper

(c)

Carbon rod

(d)

Platinum electrode

2. Zinc blende is_________

(a)

ZnS

(b)

PbS

(c)

Ag2S

(d)

Cu2S

3. Aluminium is used for making alloys because of its _____

(a)

resistance to corrosion

(b)

poor conductivity

(c)

heaviness

(d)

all of these

4. The basicity of pyrophosphorous acid ( H4P2O5) is

(a)

4

(b)

2

(c)

3

(d)

5

5. An example of a chelating ligand is

(a)

NO-2

(b)

Chloro

(c)

Bromo

(d)

en

6. The diffraction of crystal of Ba with X-ray of wavelength 2.29$\mathring { A }$ gives a first order reflection at 27°8'. What is the distance between the diffracted patterns?

(a)

5.02 $\mathring { A }$

(b)

0.398$\mathring { A }$

(c)

2.51$\mathring { A }$

(d)

10.04$\mathring { A }$

7. A crystal which has the same unit cell and contains the same lattice points throughout the crystal is_________.

(a)

perfect

(b)

imperfect

(c)

distorted

(d)

both (b) and (c)

8. What is the activation energy for a reaction if its rate doubles when the temperature is raised from 200K to 400K? (R = 8.314 JK-1mol-1)

(a)

234.65 kJ mol-1 K-1

(b)

434.65 kJ mol-1 K-1

(c)

434.65 J mol-1 K-1

(d)

334.65 J mol-1 K-1

9. The rate of a reaction is expressed as k[A]2[B]1,  the reaction is said to be

(a)

second order with respect to A

(b)

first order with respect to B

(c)

overall order of the reaction is third order

(d)

all the above

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. Faradays constant is defined as

(a)

charge carried by 1 electron

(b)

charge carried by one mole of electrons

(c)

charge required to deposit one mole of substance

(d)

charge carried by 6.22 ×1010 electrons

12. The electrical energy produced by a cell equals __________

(a)

Ecathode - Eanode

(b)

$\frac{Charge \ of \ electrons}{E_{cell}}$

(c)

Charge of electrons x Ecell

(d)

$\frac{E_{cell}}{Charge \ of \ electrons}$

13. The coagulation values in millimoles per litre of the electrolytes used for the coagulation of AS2S3 are given below
(I) (NaCl)=52 (II) ((BaCl2)=0.69 (III) (MgSO4)=0.22
The correct order of their coagulating power is

(a)

III > II > I

(b)

I > II > III

(c)

I > III > II

(d)

II > III>I

14. Extent of physisorption of a gas increases with_______

(a)

increase in temperature

(b)

decrease in surface area of adsorbent

(c)

decrease in pressure

(d)

decrease in temperature

15. The reactions

is an example of

(a)

Wurtz reaction

(b)

cyclic reaction

(c)

Williamson reaction

(d)

Kolbe reactions

16.

(a)

Acetone

(b)

Isobutylene

(c)

Acetic anhydride

(d)

Ethyl alcohol

17. Complete the reaction

(a)

(b)

(c)

(d)

none

18. In swern method of oxidation of alcohols to aldhedye/ ketones _______ is used as an oxidising agent.

(a)

dimethyl sulfoxide

(b)

pyridimium chloro chromate

(c)

CrO3 in anhydrousmedium

(d)

Na2Cr2O7 |H+

19. Identify the major product in the given reaction

(a)

(b)

(c)

(d)

20. Identify the product formed in the reaction

(a)

(b)

(c)

(d)

21. In which case chiral carbon is not generated by reaction with HCN

(a)

(b)

(c)

(d)

22. Tincture benzoin is obtained from

(a)

benzoyl chloride

(b)

benzoin

(c)

benzyl alcohol

(d)

benzoic acid

23. Among the following, the reaction that proceeds through an electrophilic substitution, is :

(a)

(b)

(c)

(d)

24. Which of the following statement is correct?

(a)

Ovalbumin is a simple food reserve in egg-white

(b)

Blood proteins thrombin and fibrinogen are involved in blood clotting

(c)

Denaturation makes protein more active

(d)

Insulin maintains the sugar level of in the human body

25. Regarding cross-linked or network polymers, which of the following statement is incorrect?

(a)

Examples are Bakelite and melamine

(b)

They are formed from bi and tri-functional monomers

(c)

They contain covalent bonds between various linear polymer chains

(d)

They contain strong covalent bonds in their polymer chain