Chemistry Question And Answer

Chemistry Question And Answer

Chemistry Question And Answer
Chemistry Question And Answer

1. The method of concentrating the ore which makes use of the difference in density between ore and impurities is called1. The method of concentrating the ore which makes use of the difference in density between ore and impurities is called
A. liquation

B. leaching

C. levigation

D. magnetic separation

Answer: Option C

2. The molecular formula of phosphorous is
A. P1

B. P2

C. P3

D. P4

Answer: Option D

3. The formula C6H5-CO-CH3 represents
A. Acetone

B. Acetic acid

C. Acetophenone

D. Phenyl acetate

Answer: Option C

4. Equal masses of oxygen, hydrogen and methane are kept under identical conditions. The ratio of the volumes of gases will be
A. 2 : 16 : 2

B. 2 : 16 : 1

C. 1 : 16 : 2

D. 1 : 1 : 1

Answer: Option C

5. The number of atoms present in 21.6 gram of silver (atomic weight = 108) are same as the molecules in
A. 1.8 gram of H2O

B. 12 moles of KMnO4

C. 0.6N H2SO4

D. 4.6 gram of C2H5OH

Answer: Option B

6. The half life period of an isotope is 2 hours. After 6 hours what fraction of the initial quantity of the isotope will be left behind?
A. 1/6

B. 1/3

C. 1/8

D. 1/4

Answer: Option C

7. The isomerism which exists between CH3CHCI2 and CH2CI. CH2CI is
A. chain isomerism

B. functional group isomerism

C. positional isomerism

D. metamerismAnswer: Option C

8. The organic reaction represented by equation CH3 – CH = O + H2NOH gives CH3 – CH – NH + H2O is an example of
A. an addition reaction

B. a condensation reaction

C. an oxidation reaction

D. an elimination reaction

Answer: Option B

9. The human body is made up of several chemical elements; the element present in the highest proportion (65%) in the body is
A. carbon

B. hydrogen

C. oxygen

D. nitrogen

Answer: Option C

10. The number of g-molecule of oxygen in 6.02 x 1024CO molecules is
A. 1 gram of molecule

B. 0.5 gram of molecule

C. 5 gram of molecule

D. 10 gram of molecule

Answer: Option C

11. The hardest form of carbon is
A. coke

B. graphite

C. diamond

D. charcoal

Answer: Option C

12. The molecule which has the highest percentage of ionic character among the following is
A. HI

B. HF

C. HCI

D. HBr

Answer: Option B

13. The following are the half lives of four active isotopes. Which one of the following is the most dangerous to handle?
A. 3 billion years

B. 100 years

C. 0.01 minute

D. 13 days

Answer: Option C

14. The graphite rods in the nuclear reactor
A. react with U to release energy

B. produce neutrons

C. undergo combustion which triggers the nuclear fission

D. convert fast moving neutrons into thermal neutrons

Answer: Option D

15. The most electropositive elements among the following is
A. Na

B. Ca

C. K

D. Cs

Answer: Option D

16. The number of water molecules present in a drop of water (volume 0.0018 ml) at room temperature is
A. 1.568 x 103

B. 6.023 x 1019

C. 4.84 x 1017

D. 6.023 x 1023

Answer: Option B

17. The main use of salt in the diet is to
A. make the taste of food better

B. produce in small amounts the hydrochloric acid required for the digestion of food

C. ease the process of cooking

D. increase the solubility of food particles in water

Answer: Option B

18. The Latin word formica means ant. The name formic acid is derived from this Latin word because
A. this acid, in ancient times, was used to eliminate ant-hills

B. this corrosive acid is secreted by ants to drive away their enemies

C. this acid was first obtained by the distillation of ants

D. ants are attracted by the odour of this acid

Answer: Option C

19. The gas present in the stratosphere which filters out some of the sun’s ultraviolet light and provides an effective shield against radiation damage to living things is
A. helium

B. ozone

C. oxygen

D. methane

Answer: Option B

20. The oldest rocks in the earth’s crust were once molten, and came from deep inside the earth. The molten rock, called magma, spewed out in volcanic eruptions during the earth;s early life and solidified into hard rock’s called
A. granite

B. basalt

C. igneous rocks

D. sedimentary rocks

Answer: Option C

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