Chemistry Test 1

Total Questions: 25

1 - Which of the following gases is used in fire extinguishers?

A ) Oxygen
B ) Hydrogen
C ) Water vapour
D ) Carbon dioxide ✅

2 - Stains of rust from iron on cloth can be removed by

A ) Hydrogen peroxide
B ) Alcohol
C ) Oxalic acid ✅
D ) Petrol

3 - Cooking gas is a mixture of which of the following two gases?

A ) Methane and Carbon dioxide
B ) Oxygen and Nitrogen
C ) Bautane and Propane ✅
D ) Oxygen and Methane

Explanation:

Cooking gas is a mixture of: Butane and Propane

  • Cooking gas is commonly known as LPG (Liquefied Petroleum Gas).
  • It mainly consists of two hydrocarbons:
    • Butane (C₄H₁₀)   Propane (C₃H₈)

🔹 Properties of LPG:

  • ✅Stored under pressure in liquid form
  • ✅Easily vaporizes to gas when released
  • ✅Highly flammable — used widely as cooking fuel.

5 - On addition of salt to water,its

A ) Boiling point increases ✅
B ) Boiling point decreases
C ) Boiling point is not affected
D ) Freezing point increases

6 - Which of the following gases doesn't pollute air?

A ) Carbon dioxide ✅
B ) Carbon monoxide
C ) Nitrogen dioxide
D ) Sulphur dioxide

7 - The inorganic natural resource of the earth is

A ) Mineral fuels ✅
B ) Wood
C ) Coal
D ) Microbes

8 - Which of the following has the highest fuel value?

A ) Hydrogen ✅
B ) Charcoal
C ) Natural gas
D ) Gasoline

9 - The characteristics odour of garlic is due to

A ) A chloro compound
B ) A sulphur compound ✅
C ) A flourine compound
D ) Acetic acid

10 - Which of the following group of compounds constitute carbohydrates?

A ) Fats and sugar
B ) Fats,sugar and proteins
C ) Starch,sugar and proteins
D ) Starch and sugar ✅

11 - What is the chemical name of Baking Soda?

A ) Sodium bicarbonate ✅
B ) Sodium Nitrate
C ) Sodium Carbonate
D ) Potassium

12 - Milk lacks in one important nutrient; which?

A ) Calcium
B ) Iron ✅
C ) Potassium
D ) Protein

13 - Ripening of fruits is hastened by which of the following gases

A ) Hydrogen
B ) Carbon dioxide
C ) Methane
D ) Ethylene ✅

14 - Iron articles rust because of the formation of

A ) Ferrous chloride
B ) A mixture of ferrous and ferric hydroxide ✅
C ) Sodium Carbonate
D ) Ferric chloride

15 - Gunpowder consists of

A ) 75% potassium nitrate+15%charcoal+10% sulphur
B ) 75% potassium nitrate+10% charcoal+15% sulphur
C ) 75% potassium nitrate+10% charcoal+15% sulphur
D ) 75% potassium nitrate+15% charcoal+15% sulphur ✅

16 - X-rays are produced when a stream of electrons in an X-ray tube?

A ) Hits the glass wall of the tube
B ) Strikes metal target ✅
C ) Pass through a strong magnetic field
D ) None

17 - In the periodic table, elements have been arranged?

A ) In order of increasing volume
B ) In order of increasing atomic number ✅
C ) In order of increasing atomic weights
D ) In order of increasing density

18 - Which group of elements in the periodic table show highest first ionisation potential. Elements in the

A ) Left hand top corner ✅
B ) Left hand bottom corner
C ) Right hand top corner
D ) Right hand bottom corner

19 - Generally in a given period in the periodic table,as we move from left to right, the electropositive character of elements

A ) Increases
B ) Decreases ✅
C ) Neither increases nor decreases
D ) Decorations then increases

20 - Atom bomb is based on the principle of?

A ) Nuclear fusion
B ) Nuclear fission ✅
C ) Radioactive
D ) Nuclear fission and fusion both

21 - Oxidation involves:

A ) Gain in electrons
B ) Gain of hydrogen
C ) Loss of electrons ✅
D ) Combustion

22 - The substances are radioactive, which have?

A ) Electrons in their nuclei
B ) Nuclei with less number of neutrons
C ) Unstable nuclei ✅
D ) Electrons removed from the outermost shell

Explanation:
  1. Radioactivity was  discovered by Becquerel.
  2. Radioactivity emerges from: Nuclear energy.
  3. Radioactivity is measured by which device Geiger counter.
  4. Thorium metal is not only magnetic but also radioactive Radioactive element are Plutonium, Thorium, Uranium.
  5.  Alpha rays is a positively charged particle emitted by a radioactive element.
  6. A negatively charged particle emitted by a radioactive element during radioactive decay is called a beta particle.
  7. Radioactive isotopes are used in medicine for both diagnostic imaging and treatment.
  8. A 100 g sample of a radioactive element has a half life of 5 days. 12.5grams of radioactive material will remain after 15 days.
  9. Radioactive elements have atomic number greater than82.
  10. Weak Nuclear Force is responsible for the radioactive decay of the nucleus.
  11. The radioactive material must be placed in a box of Lead.
  12. Radioactive cobalt 60 is used for curing: Cancerous cells.
  13. Radioactive isotope present in atmosphere is: carbon -14.
  14. Unstable nuclei  are radioactive.When radioactivity rays are passed through air or any gas, they cause it to Ionize.

24 - Nuclear Power reactors are operated at low temperatures and consequently with lower efficiency because?

A ) Nuclear heat is carried by ordinary system
B ) Uranium is difficult to heat
C ) The walls of nuclear reactors can not withstand high temperature ✅
D ) High pressure inside the reactor reduces the temperature

25 - The energy emitted from the sun is supposed to be due to

A ) Nuclear fission
B ) Nuclear fusion ✅
C ) Combustion of hydrogen
D ) Combustion of He