1. Sodium chloride (table salt) occurs naturally as the mineral:
a) Sylvite
b) Talc
c) Halite
d) Sphalerite
Answer: c
2. Which metal is used in storage batteries?
a) Copper
b) Lead
c) Tin
d) Zinc
Answer: b
3. Plaster of Paris is prepared by partial dehydration of:
a) Green vitriol
b) Blue vitriol
c) Gypsum
d) Epsom salt
Answer: c
4. Which elements are essential for maintaining a healthy human body?
a) Cobalt and Phosphorus
b) Phosphorus and Zinc
c) Cobalt and Zinc
d) Cobalt, Phosphorus, and Zinc
Answer: d
5. Which of the following is a noble gas?
a) Nitrogen
b) Hydrogen
c) Chlorine
d) Helium
Answer: d
6. What is commonly known as Saltpeter?
a) NaCl
b) KNO₃
c) Na₂CO₃
d) NaHCO₃
Answer: b
7. Lead content in lead pencils is:
a) 0%
b) 31–66%
c) 40%
d) 80%
Answer: a
8. Diamond is an allotropic form of:
a) Germanium
b) Carbon
c) Silicon
d) Sulphur
Answer: b
9. Which of the following is a biochemical sedimentary rock?
a) Marble
b) Coal
c) Granite
d) Slate
Answer: b
10. Deep sea divers use a gas mixture of oxygen and:
a) Argon
b) Helium
c) Helium and Nitrogen
d) Hydrogen
Answer: c
11. The order of increasing thermal conductivity among aluminium, copper, and stainless steel is:
a) Copper < Aluminium < Stainless Steel
b) Stainless Steel < Aluminium < Copper
c) Aluminium > Copper < Stainless Steel
d) Copper < Stainless Steel < Aluminium
Answer: b
12. Smoke bombs are made using:
a) Sulphur
b) Phosphorus
c) Hydrogen
d) Carbon
Answer: b
13. Chemical name of ‘Hypo’ used in photography is:
a) Sodium thiosulphate
b) Silver nitrate
c) Sodium nitrate
d) Silver iodide
Answer: a
14. When hard water evaporates completely, the residue may contain:
a) Carbonates and sulphates of Ca and Mg
b) Carbonates, sulphates, and chlorides of Ca and Mg
c) Chlorides only
d) Sulphates and chlorides only
Answer: d
15. The chemical formula of aluminium chloride is:
a) AlCl
b) AlCl₂
c) AlCl₃
d) Al₂Cl₃
Answer: c
16. Which compound is used in gunpowder?
a) Magnesium sulphate
b) Potassium nitrate
c) Sodium stearate
d) Calcium sulphate
Answer: b
17. PH₃ (phosphine) is an example of a:
a) Ionic hydride
b) Covalent hydride
c) Metallic hydride
d) Polymeric hydride
Answer: b
18. The electromagnetic wave emitted from a radioactive nucleus is:
a) Alpha ray
b) Beta ray
c) Gamma ray
d) Microwave
Answer: c
19. Element with the lowest melting point:
a) Helium
b) Potassium
c) Tungsten
d) Sulphur
Answer: a
20. Temporary hardness in water is due to:
a) Magnesium bicarbonate
b) Calcium carbonate
c) Calcium chloride
d) Magnesium sulphate
Answer: a
21. Which substance is used in making pencil cores?
a) Charcoal
b) Bone black
c) Black ash
d) Graphite
Answer: d
22. Water is an excellent solvent because its molecules are:
a) Highly polar
b) Non-polar
c) Light-weight
d) Neutral
Answer: a
23. Solid carbon dioxide is also called:
a) Hypo
b) Borax
c) Alum
d) Dry ice
Answer: d
24. Why is graphite used in electrolytic cells?
a) It’s soft and easily molded
b) Made of carbon layers that slide
c) Chemically inert
d) Good conductor of electricity
Answer: d
25. Major pollutants from steel industries include:
a) Sulphur oxides, CO, CO₂
b) Nitrogen oxides, CO
c) CO and CO₂
d) All of the above
Answer: d
26. Metals conduct electricity due to the presence of:
a) Low melting point
b) High tensile strength
c) Free electrons
d) High atomic density
Answer: c
27. Sulphur dioxide bleaches by:
a) Decomposition
b) Oxidation
c) Reduction
d) Dehydration
Answer: c
28. Fullerene (a carbon allotrope) was discovered by:
a) K. Scheele
b) Richard Smalley
c) Faraday
d) Heisenberg
Answer: b
29. Which gas is colored?
a) Oxygen
b) Nitrogen
c) Chlorine
d) Hydrogen
Answer: c
30. The strong garlic smell is due to the presence of:
a) A chloro compound
b) A sulphur compound
c) A fluorine compound
d) Acetic acid
Answer: b
31. Ozone contains:
a) Only oxygen
b) Oxygen and nitrogen
c) Hydrogen and carbon
d) Oxygen and carbon
Answer: a
32. Assertion (A): Acid is added to water, not water to acid, when diluting sulphuric acid.
Reason (R): Water has a high specific heat.
a) Both A and R are true, and R explains A
b) Both A and R are true, but R does not explain A
c) A is true, R is false
d) A is false, R is true
Answer: a
33. Hydrogen was discovered by:
a) Boyle
b) Charles
c) Cavendish
d) Priestly
Answer: c