The following 20 Multiple Choice Questions (MCQ) are based on
Chapter 4: The World of Metals and Non-metals from the NCERT Class 7
Science textbook Curiosity. Each question has four options - select the
best answer and click to check.
Instructions: Read each question carefully. Choose the most
appropriate option from (a), (b), (c), or (d). Click
Show Answer to reveal the correct answer with explanation.
Multiple Choice Questions
1Malleability is the ability of a material to be:
(a) Beaten into thin sheets
(b) Drawn into wires
(c) Made to ring
(d) Dissolved in water
(a) is correct
Many metals flatten under hammering without breaking.
2Ductility is the ability to be:
(a) Beaten into sheets
(b) Broken into powder
(c) Dissolved in acid
(d) Drawn into wires
(d) is correct
Copper and aluminium can be pulled into long wires.
3Sonorous materials produce:
(a) Only heat
(b) An acidic solution
(c) A ringing sound when struck
(d) No sound
(c) is correct
Many metals ring when struck and are described as sonorous.
4Which property makes copper suitable for cooking vessels?
(a) Low strength only
(b) Good heat conductivity
(c) Poor heat conductivity
(d) Brittleness
(b) is correct
Copper transfers heat efficiently to the food or water.
5Which property makes metals useful for electrical wires?
(a) Electrical conductivity and ductility
(b) Brittleness and dullness
(c) Acidic oxides only
(d) Poor conductivity
(a) is correct
A wire must carry current and be drawable into long thin lengths.
6Which is generally a metal?
(a) Sulfur
(b) Oxygen
(c) Carbon
(d) Iron
(d) is correct
Iron shows typical metallic properties such as lustre, strength and conductivity.
7Which is a non-metal?
(a) Aluminium
(b) Iron
(c) Sulfur
(d) Copper
(c) is correct
Sulfur is dull, brittle and a poor conductor.
8Most solid non-metals are:
(a) Good electrical conductors
(b) Brittle rather than malleable
(c) Highly ductile
(d) Sonorous
(b) is correct
They tend to break when hammered instead of flattening.
9Rusting of iron requires:
(a) Oxygen and water
(b) Only dry nitrogen
(c) Only sunlight
(d) Kerosene
(a) is correct
Both air and moisture are necessary for significant rust formation.
10Which iron nail is least likely to rust?
(a) One dipped in water and exposed to air
(b) One in moist air
(c) One in vinegar exposed to air
(d) One completely protected by oil
(d) is correct
An oil layer blocks contact with oxygen and water.
11Galvanisation protects iron by coating it with:
(a) Carbon
(b) Wood
(c) Zinc
(d) Sulfur
(c) is correct
The zinc coating separates iron from air and moisture and offers additional protection.
12Why is sodium stored in kerosene?
(a) It does not react with anything
(b) It reacts vigorously with air and moisture
(c) It is a non-metal
(d) Kerosene makes it edible
(b) is correct
Kerosene prevents dangerous contact with oxygen and water.
13When magnesium burns in oxygen, it forms:
(a) Magnesium oxide
(b) Sulfur dioxide
(c) Iron oxide
(d) Magnesium metal again
(a) is correct
Brightly burning magnesium combines with oxygen to produce magnesium oxide.
14A solution of many metal oxides in water is generally:
(a) Acidic
(b) Always neutral
(c) A metal
(d) Basic
(d) is correct
Metal oxides such as magnesium oxide commonly show basic nature.
15Burning sulfur in oxygen produces:
(a) Hydrogen
(b) Iron rust
(c) Sulfur dioxide
(d) Magnesium oxide
(c) is correct
Sulfur reacts with oxygen to form the gaseous non-metal oxide sulfur dioxide.
16Sulfur dioxide dissolved in water forms a solution that is:
(a) Always neutral
(b) Acidic
(c) Basic
(d) Metallic
(b) is correct
It forms sulfurous acid, which turns blue litmus red.
17Oxygen is essential for many organisms because it supports:
(a) Respiration
(b) Metal ductility
(c) Rust prevention
(d) Electrical insulation
(a) is correct
Cells use oxygen to release energy from food.
18Nitrogen is important in agriculture because it is used in:
(a) Only jewellery
(b) Electrical insulation
(c) Mirrors
(d) Fertilisers
(d) is correct
Plants need nitrogen compounds to make proteins and grow.
19Chlorine is commonly used for:
(a) Stopping all combustion
(b) Producing copper wire
(c) Water purification
(d) Making iron malleable
(c) is correct
Controlled chlorination kills many harmful microorganisms in water.
20Plastic and glass are not classified as elements that are metals or non-metals because they:
(a) Are single elemental atoms
(b) Are materials made from more than one kind of substance
(c) Are always metals
(d) Contain no matter
(b) is correct
Metal and non-metal categories here apply to elements, whereas plastic and glass are complex materials.
