Chemistry · Science General

Common Chemical Compounds and Reactions

1,204 Questions

Common chemical compounds and reactions questions test your knowledge of everyday chemicals, their formulas, and their interactions. Topics include properties of acids and bases, hard water chemistry, and compounds like baking soda and plaster of paris. This section is essential for general science preparation.

Acids and basesPlaster of parisHard water chemistryCommon chemical formulasEveryday chemical reactions

Common Chemical Compounds and Reactions Questions

Multiple choice

Soap molecules form __________ with hard water.

  1. lather

  2. scum

  3. precipitate

  4. both 1 and 2

  5. both 2 and 3
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Yes, this is the correct option. With hard water soap solutions form a white precipitate and off white layer over water known as soap scum, instead of producing lather.

Multiple choice

Why are detergents preferred over soap in hard water?

  1. They are free flowing and easily available.

  2. They do not precipitate with calcium or magnesium salts in hard water.

  3. They change the hard water into soft water.

  4. They form scum, which can easily be removed.

  5. They have fresh odour.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, detergents are ammonium or sulphonate salts of carboxylic acids. The charged ends of these compounds do not form precipitates with calcium or magnesium salts in hard water. Hence, detergents retain their cleansing property in hard water.

Multiple choice

What is common salt?

  1. Sodium chloride

  2. Sodium carbonate

  3. Sodium bicarbonate

  4. Sodium phosphate
Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice

Methyl phenol, hydrogen peroxide and sulphur dioxide are the most common examples of

  1. antiseptic products

  2. disinfectants

  3. antacids

  4. antihistamines
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Disinfectants are used to kill bacteria. They are used to sterilize instruments, utensils, clothes, floors, sanitary fittings, sputum and excreta. They harm the living tissues and cannot be used on skin. Some examples are phenol, methyl phenol, hydrogen peroxide and sulphur dioxide.

Multiple choice

Anhydrous calcium chloride, quick lime and concentrated sulphuric acid act as

  1. drying agents

  2. cleansing agents

  3. oxidizing agents

  4. reducing agents
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Substances that are capable of taking away moisture from a gas are called drying agents. As all deliquescent and hygroscopic substances have affinity for water, they can be used as drying agents. However, usually anhydrous calcium chloride, quick lime and concentrated sulphuric acid are used as drying agents in the laboratory.

Multiple choice

Which of the following can be excluded from the properties of detergents?

  1. Detergents are sodium salts of long chain benzene sulphonic acid

  2. Calcium and magnesium salts of detergents are insoluble in water.

  3. Synthetic detergents are prepared from hydrocarbons of petroleum

  4. Most of the detergents are non-biodegradable
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Calcium and magnesium salts of detergents are soluble in water. Therefore, cleansing action of detergents remains unaffected in hard water.

Multiple choice

Which of the following sequence correctly represents the percentage of given salts in sea water in decreasing order?

  1. Magnesium chloride - Sodium chloride - Magnesium sulphate - Calcium sulphate

  2. Magnesium sulphate - Magnesium chloride - Calcium sulphate - Sodium chloride

  3. Sodium chloride - Magnesium chloride - Magnesium sulphate - Calcium sulphate

  4. Sodium chloride - Magnesium sulphate - Magnesium chloride - Calcium sulphate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sea water contains various dissolved salts, with sodium chloride (NaCl) being the most abundant at about 77.8%, followed by magnesium chloride (MgCl2) at about 10.9%, magnesium sulphate (MgSO4) at about 1.2%, and calcium sulphate (CaSO4) at about 0.3%. The decreasing order correctly represents their relative abundance in ocean water.

Multiple choice

The mixture of RDX, TNT and aluminium powder is

  1. DBX

  2. Tropex

  3. Cordite(MD)

  4. Cordite

  5. (1) and (2) both are correct
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is wrong because these are the secondary explosives. 50% more powerful than TNT by mass, torpex comprises of 42% RDX, 40% TNT, and 18% powdered aluminium.