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

12th Standard

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Chemistry

Time : 00:25:00 Hrs
Total Marks : 25
Answer all the questions
25 x 1 = 25
1. The metal oxide which cannot be reduced to metal by carbon is ____________

(a)

PbO

(b)

AL2O3

(c)

ZnO

(d)

Feo

2. Which one of the following ores is best concentrated by froth – floatation method?

(a)

Magnetite

(b)

Hematite

(c)

Galena

(d)

Cassiterite

3. Among the following, one does not belong to calcination, Pick the odd one out.

(a)

${ PBCO }_{ 3 }\overset { \Delta }{ \longrightarrow } PBO+{ CO }_{ 2 }\uparrow$

(b)

${ CaCo }_{ 3 }\overset { \Delta }{ \longrightarrow } Cao+{ CO }_{ 2 }\uparrow$

(c)

$PbS{ O }_{ 3 }\overset { \Delta }{ \rightarrow } PbO+{ 2SO }_{ 2 }\uparrow$

(d)

${ ZnCO }_{ 3 }\overset { \Delta }{ \rightarrow } ZnO+{ CO }_{ 2 }\uparrow$

4. Carbon atoms in fullerene with formula C60 have __________

(a)

sp3 hybridised

(b)

sp hybridised

(c)

sp2 hybridised

(d)

partially sp2 and partially sp3 hybridised

5. An element belongs to group 15 and 3rd period of the periodic table, its electronic configuration would be _____________

(a)

1s2 2s2 2p4

(b)

1s2 2s2 2p3

(c)

1s2 2s2 2p6 3s2 3p2

(d)

1s2 2s2 2p6 3s2 3p3

6. Strong reducing behaviour of H3PO2 is due to______

(a)

High oxidation state of phosphorus

(b)

High electro gain enthalpy of phosphorus

(c)

Presence of two-OH groups and one P-H bond

(d)

Presence of one-OH groups and two P-H bonds

7. Which of the following d block element has half filled penultimate d sub shell as well as half filled valence sub shell?

(a)

Cr

(b)

Pd

(c)

Pt

(d)

none of these

8. The alloy of copper that contain Zinc is

(a)

Monel metal

(b)

Bronze

(c)

bell metal

(d)

brass

9. Sometimes vessels made of copper or bronze show traces of green colour. This is due to the formation of ___________________

(a)

Cu(OH)2

(b)

CuCO3

(c)

Cu(OH)2CuCO3

(d)

Cu(OH)2CuSO4

10. IUPAC name of the complex K3[Al(C2O4)3] is ____________

(a)

potassiumtrioxalatoaluminium(III)

(b)

tassiumtrioxalatoaluminate(II)

(c)

potassiumtrisoxalatoaluminate(III)

(d)

potassiumtrioxalatoaluminate(III)

11. The name of complex ion, [Fe(CN)6]3- is

(a)

Trieyanoferrate (III) ion

(b)

Hexacyano iron (III) ion

(c)

Hexacyanitoferrate (III) ion

(d)

Hexacyanido ferrate (III) ion

12. The chemical formula for diammine silver (I) chloride is __________

(a)

[Ag(NH3)2] Cl

(b)

[Ag(NH3)]Cl

(c)

[Ag(NH2)2]Cl

(d)

[Ag(NH4)2]Cl

13. The fraction of total volume occupied by the atoms in a simple cubic is ___________

(a)

$\left( \cfrac { \pi }{ 4\sqrt { 2 } } \right)$

(b)

$\left( \cfrac { \pi }{ 6 } \right)$

(c)

$\left( \cfrac { \pi }{ 4 } \right)$

(d)

$\left( \cfrac { \pi }{ 3\sqrt { 2 } } \right)$

14. After 2 hours, a radioactive substance becomes $\left( \cfrac { 1 }{ 16 } \right) ^{ th }$ of original amount Then the half life ( in min) is ___________

(a)

60 minutes

(b)

120 minutes

(c)

30 minutes

(d)

15 minutes

15. What would be the activation energy of a reaction when the temperature is increased from 27oC to 37oC?

(a)

534 kJ mol-1

(b)

53.4 kJ mol-1

(c)

5.34 kJ mol-1

(d)

None of these

16. For a reaction: aA ⟶ bB, the rate of reaction is doubled when the concentration of A is increased by four times. The rate of reaction is equal to

(a)

k[A]a

(b)

$k{ \left[ A \right] }^{ \frac { 1 }{ 2 } }$

(c)

$k{ \left[ A \right] }^{ \frac { 1 }{ a } }$

(d)

K[A]

17. MY and NY3, are insoluble salts and have the same Ksp values of 6.2 ×10-13 at room temperature. Which statement would be true with regard to MY and NY3?

(a)

The salts MY and NY3 are more soluble in 0.5M KY than in pure water

(b)

The addition of the salt of KY to the suspension of MY and NY3 will have no effect on their solubility’s

(c)

The molar solubilities of MY and NY3 in water are identical

(d)

The molar solubility of MY in water is less than that of NY3

18. Which among the following has the highest pH?

(a)

1M NH4 OH

(b)

1M HCI

(c)

1M NaOH

(d)

0.1 M NaOH

19. Using the data given below fmd out the strongest reducing agent
${ E }_{ { Cr }_{ 2 }{ O }_{ 7 }^{ 2- } }^{ o }{ Cr }^{ 3+ }=1.33V{ ,E }_{ { Cl }_{ 2 }{ / }{ Cl }^{ - } }^{ o }=1.36V$
${ E }_{ { Mn }O_{ 4 }^{ - } }^{ 0 }/{ Mn }^{ 2+ }=1.51V,{ E }_{ { Cr }^{ 3+ }/Cr }^{ o }=-0.74V$

(a)

Cr

(b)

Cr3+

(c)

Cl-

(d)

Mn2+

20. The standard conditions for determination of standard emf of the cell are

(a)

1M solution of the reactant

(b)

temperature of 25°C

(c)

both 1M solution of the reactant and temperature of 25°C

(d)

none of these

21. In the reaction Ethanol $\overset { { PCl }_{ 5 } }{ \longrightarrow } X\overset { alc.KOH }{ \longrightarrow } Y\overset { { H }_{ 2 }{ SO }_{ 4 }/{ H }_{ 2 }O }{ \underset { 298k }{ \longrightarrow } } Z.$ The ‘Z’ is _____________

(a)

ethane

(b)

ethoxyethane

(c)

ethylbisulphite

(d)

ethanol

22. CH3Br $\overset { KCN }{ \longrightarrow } (A)\overset { { H }_{ 2 }{ O }^{ + } }{ \longrightarrow } (B)\overset { { PCl }_{ 5 } }{ \longrightarrow }$ (C) product (c) is ____________

(a)

acetylchloride

(b)

chloro acetic acid

(c)

$\alpha$- chlorocyano ethanoic acid

(d)

none of these

23. The correct corresponding order of names of four aldoses with configuration given below Respectively is __________

(a)

L-Erythrose, L-Threose, L-Erythrose, D-Threose

(b)

D-Threose,D-Erythrose, L-Threose, L-Erythrose,

(c)

L-Erythrose, L-Threose, D-Erythrose, D-Threose

(d)

D-Erythrose, D-Threose, L-Erythrose, L-Threose

24. Saccharin, an artificial sweetener is manufactured from ____________.

(a)

cellulose

(b)

toluene

(c)

cyclohexene

(d)

starch