Everyday Science · Topic 2
Common chemicals, the air, pollution and climate agreements.
Learn first
Learn the chemical names of household substances, the make-up of air and the main pollution and climate facts.
Practise
Try each question, then open the answer. MCQs 1–50 of 346.
1.What is the chemical formula of water?
Answer: A. H₂O
A water molecule has two hydrogen atoms and one oxygen atom.
2.What is the chemical name of common table salt?
Answer: B. Sodium chloride
Table salt is sodium chloride, NaCl.
3.What is the chemical name of baking soda?
Answer: C. Sodium bicarbonate
Baking soda is sodium bicarbonate (sodium hydrogen carbonate), NaHCO₃.
4.What is the chemical name of washing soda?
Answer: A. Sodium carbonate
Washing soda is hydrated sodium carbonate, Na₂CO₃·10H₂O.
5.What is the chemical name of caustic soda?
Answer: D. Sodium hydroxide
Caustic soda, used in soap making, is NaOH.
6.What is the chemical name of quicklime?
Answer: D. Calcium oxide
Quicklime is CaO.
7.What is the chemical name of slaked lime?
Answer: C. Calcium hydroxide
Slaked lime is Ca(OH)₂, used in whitewash.
8.Limestone, marble and chalk are mainly which compound?
Answer: D. Calcium carbonate
All three are forms of calcium carbonate, CaCO₃.
9.Plaster of Paris is made from which mineral?
Answer: C. Gypsum
Heating gypsum (calcium sulphate) gives Plaster of Paris.
10.What is the common name of nitrous oxide?
Answer: C. Laughing gas
Nitrous oxide (N₂O) is called laughing gas and is used as an anaesthetic.
11.What is the common name of methane?
Answer: B. Marsh gas
Methane is produced in marshes and is the main part of natural gas.
12.CNG used in vehicles is mainly which gas?
Answer: A. Methane
Compressed natural gas is mostly methane.
13.LPG is mainly a mixture of which gases?
Answer: B. Propane and butane
Liquefied petroleum gas is mostly propane and butane.
14.Which gas is added to LPG to help detect leaks by smell?
Answer: C. Ethyl mercaptan
LPG has no smell; a mercaptan is added so leaks can be noticed.
15.Which gas makes up most of the Earth's atmosphere?
Answer: C. Nitrogen
Nitrogen is about 78 per cent of the air.
16.About what percentage of the air is oxygen?
Answer: A. 21 per cent
Oxygen makes up about 21 per cent of dry air.
17.Which is the third most abundant gas in the air?
Answer: A. Argon
Argon (about 0.93 per cent) comes after nitrogen and oxygen.
18.About what percentage of the air is carbon dioxide?
Answer: A. About 0.04 per cent
Carbon dioxide is about 0.04 per cent (over 420 parts per million).
19.Which gas do plants take in for photosynthesis?
Answer: C. Carbon dioxide
Plants use carbon dioxide and water to make sugar, giving off oxygen.
20.Which gas is given off by plants during photosynthesis?
Answer: B. Oxygen
Oxygen is released as a by-product of photosynthesis.
21.Which gas is used in fire extinguishers?
Answer: C. Carbon dioxide
Carbon dioxide does not burn and cuts off oxygen from the fire.
22.Solid carbon dioxide is commonly called what?
Answer: A. Dry ice
Dry ice turns straight into gas without melting.
23.Which gas is filled in balloons because it is light and does not burn?
Answer: C. Helium
Helium is light and non-flammable; hydrogen is lighter but explosive.
24.Which is the lightest gas?
Answer: B. Hydrogen
Hydrogen is the lightest element.
25.Which gas is used in advertising signs that glow red-orange?
Answer: A. Neon
Neon glows red-orange in discharge tubes.
26.Which gas is filled in ordinary electric bulbs to protect the filament?
Answer: C. Argon
Inert argon (often with nitrogen) stops the filament from burning out.
27.Which gas is used to disinfect drinking water?
Answer: C. Chlorine
Chlorine kills germs in drinking water.
28.Which poisonous gas is released by incomplete burning of fuel?
Answer: B. Carbon monoxide
Carbon monoxide blocks the blood's ability to carry oxygen.
29.Why is carbon monoxide dangerous?
Answer: D. It binds with haemoglobin and stops oxygen transport
It combines with haemoglobin far more strongly than oxygen does.
30.Which gas leaked in the Bhopal disaster of 1984?
Answer: C. Methyl isocyanate
Methyl isocyanate leaked from a pesticide plant in Bhopal.
31.Which gas smells like rotten eggs?
Answer: B. Hydrogen sulphide
Hydrogen sulphide (H₂S) has a rotten-egg smell.
32.What is the pH of pure water?
Answer: D. 7
Pure water is neutral, with a pH of 7.
33.A solution with a pH below 7 is what?
Answer: B. Acidic
Below 7 is acidic; above 7 is basic (alkaline).
34.Which acid is found in the human stomach?
Answer: D. Hydrochloric acid
The stomach produces hydrochloric acid to help digestion.
35.Which acid is found in vinegar?
Answer: D. Acetic acid
Vinegar is a dilute solution of acetic acid.
36.Which acid is found in lemons and oranges?
Answer: C. Citric acid
Citrus fruits contain citric acid.
37.Which acid is found in sour milk and curd?
Answer: C. Lactic acid
Bacteria turn milk sugar into lactic acid.
38.Which acid is found in ant stings?
Answer: A. Formic acid
Ants inject formic acid.
39.Which acid is found in tamarind and grapes?
Answer: B. Tartaric acid
Tartaric acid is found in tamarind and grapes.
40.Which acid is found in apples?
Answer: C. Malic acid
Apples contain malic acid.
41.Which acid is used in car batteries?
Answer: D. Sulphuric acid
Lead-acid batteries use dilute sulphuric acid.
42.Which acid is called the "king of chemicals"?
Answer: D. Sulphuric acid
Sulphuric acid is used in so many industries that it is called the king of chemicals.
43.A mixture of nitric acid and hydrochloric acid that dissolves gold is called what?
Answer: C. Aqua regia
Aqua regia (royal water) is one part nitric acid and three parts hydrochloric acid.
44.Which substance is used to treat acidity in the stomach?
Answer: A. Antacids (bases such as magnesium hydroxide)
Antacids are mild bases that neutralise excess stomach acid.
45.Which indicator turns red in acid and blue in base?
Answer: D. Litmus
Blue litmus turns red in acid; red litmus turns blue in base.
46.Brass is an alloy of which metals?
Answer: D. Copper and zinc
Brass is copper and zinc.
47.Bronze is an alloy of which metals?
Answer: B. Copper and tin
Bronze is copper and tin.
48.Steel is an alloy mainly of which elements?
Answer: D. Iron and carbon
Steel is iron with a small amount of carbon.
49.Stainless steel contains iron, carbon and which other main metal?
Answer: A. Chromium
Chromium (often with nickel) stops stainless steel from rusting.
50.Solder, used to join wires, is an alloy of which metals?
Answer: D. Tin and lead
Traditional solder is tin and lead.
Test yourself
Each quiz has 50 MCQs from this topic and 50 minutes. A correct answer earns 1 mark and each wrong answer takes off 0.25; skipped questions score nothing. No password needed.
