Chapter 4 of CBSE Class 8 Science, deals with a topic like materials- metals and non-metals. It is an important topic and answering the MCQs prepared based on the concepts of this chapter will help the students to prepare more competently for the exams. Students can find the CBSE Class 8 Science Chapter 4 Metals and Non-Metals Objective Questions with solutions for practice. More students are advised to solve these questions as it will help them get more acquainted with the MCQs that are likely to be asked in the exams.
Sub-Topics List From Chapter 4
Some of the concepts discussed in topics under this chapter include reaction with oxygen, reaction with water, reactions with acids, displacement reactions and so on. The complete list of topics is given below:
4.1 Physical Properties of Metals and Non-Metals
4.2 Chemical Properties of Metals and Non-Metals
4.3 Uses of Metals and Non-Metals
Metals and Non-Metals
21. Which of the following metals catch fire on reaction with air?
Answer: (C) Potassium
Solution: Sodium and potassium both are extremely reactive and react with air as well as water vigorously. The reactions are highly exothermic and hence, the hydrogen gas evolved as byproduct catches fire.
22. When MgO is dissolved in water, Mg(OH)2 is obtained. The solution thus obtained is ___ in nature.
Answer: (B) alkaline
Solution: An alkaline or basic solution turns red litmus paper to blue. Hence when a red litmus paper is dipped into this solution of Mg(OH)2, it turns blue indicating the basic nature of the solution.
23. Which of the following metals do not react even with steam.?
Answer: (A) Silver
Solution: The reactivity of silver is so low that it doesn’t react even with steam.
24. Identify the non-metal which exists in a liquid state in room temperature 25∘C.
Answer: (D) Bromine
Solution: Amongst the given options, mercury and aluminium are metals while iodine and bromine are non-metals. Bromine is a reddish-brown liquid at room temperature.
25. Which of the following pairs of compounds undergo displacement reaction when they react with each other?
A. Cu and AgNO3 solution
B. Ag and FeSO4 solution
C. Cu and NaCl solution
D. Mg and NaCl solution
Answer: (A) Cu and AgNO3 solution
Solution: Silver nitrate and copper metal undergoes displacement reaction as copper is more reactive than silver. Hence, it displaces silver to form copper nitrate.
26. A reaction in which a more reactive metal replaces a less reactive metal from its salt solution is called a/an ________ reaction.
C. double displacement
Answer: (B) displacement
Solution: When one metal replaces another metal from its salt solution, the type of reaction is termed as a displacement reaction.
27. Food cans are coated with tin and not with zinc because:
A. Zinc is less reactive than tin.
B. Zinc is more reactive than tin.
C. Zinc has a higher melting point than tin.
D. Zinc is costlier than tin.
Answer: (B) Zinc is more reactive than tin.
Solution: Zinc is more reactive than tin. Tin only reacts with very strong acids. However, zinc can react with simple acids found in food. Hence, in order to prevent food poisoning, the food cans are coated with a cheap, less reactive metal like tin.
28. Metals, except Al and Zn, react with oxygen to form _______ oxides.
Answer: (D) basic
Solution: Most of the metals react with oxygen to form metal oxides.
For example: magnesium reacts with oxygen to form magnesium oxide. The reaction involved is:
The metal oxide form alkali solution when dissolved in water. This solution turns red litmus paper to blue. Hence, these metal oxides are basic in nature.
29. When sulphur reacts with oxygen, the oxide formed is ___ in nature.
Answer: (D) acidic
Solution: The reaction of sulphur and oxygen gives sulphur dioxide gas. The reaction involved is:
When sulphur dioxide is dissolved in water, sulphurous acid is formed. It turns blue litmus paper red. The reaction involved is:
Hence, the oxide formed is acidic in nature.
30. Metals like zinc and aluminium react with sodium hydroxide to produce ____ gas.
B. hydrogen sulphide
D. sulphur dioxide
Answer: (A) hydrogen
Solution: Metals react with sodium hydroxide to produce hydrogen gas. For example, sodium hydroxide reacts with zinc to produce sodium zincate and hydrogen gas. Similarly, sodium hydroxide reacts with aluminium to produce sodium aluminate and hydrogen gas.
31. When zinc reacts with dilute sulphuric acid, a salt is formed with the release of a gas. The gas produced during this puts off a burning candle with a pop sound. The gas evolved during this reaction is:
A. sulphur dioxide
D. hydrogen sulphide
Answer: (C) hydrogen
Solution: Hydrogen gas is evolved mostly when a metal reacts with an acid. When zinc reacts with dilute sulphuric acid, zinc sulphate, a salt is formed with the release of hydrogen gas. The reaction involved is:
When a burning matchstick is brought near the test tube containing hydrogen gas, it puts off the burning matchstick and produces a pop sound.
32. The property by which metals can be beaten into sheets is known as ___
Answer: (D) malleability
Solution: Malleability is the property of metals by virtue of which they can be beaten into sheets. Gold is the most malleable metal.
33. The property of metal by which it can be drawn into wires is called _____.
Answer: (C) ductility
Solution: The property of metal by which it can be drawn into wires is called ductility. Example, copper and aluminium wires are widely used.
34. Which of the following can be beaten into thin sheets?
Answer: (A) Zinc
Solution: Zinc is a malleable metal and thus can be beaten into thin sheets. Phosphorus, sulphur and oxygen are all non-metals. Non-metals are usually not malleable.
35. A substance is said to be sonorous if it _________.
A. conducts heat
B. conducts electricity
C. conducts water through metal pipes
D. produces a ringing sound when beaten
Answer: (D) produces a ringing sound when beaten
Solution: Substances that produce a ringing sound when they are beaten are said to be sonorous. Metals are generally sonorous.
36. Pick the odd one from the following elements.
Answer: (C) Carbon
Solution: Out of these only Carbon (C) is a non-metal whereas the others are all metals.
37. Which of the following statements is false?
A. Carbon is the most malleable metal.
B. Copper is a good conductor of electricity.
C. Aluminium is a good conductor of heat.
D. Bromine is the only liquid non-metal.
Answer: (A) Carbon is the most malleable metal.
Solution: Carbon is a non-metal. Gold is the most malleable of all metals.
38. What is the property that makes metals shine called?
Answer: (D) Lustre
Solution: Metals have a unique ability to reflect light from their pure surface (without impurities). This results in a shiny surface and this property is known as lustre.
39. Which of the following is a non-metal but is lustrous?
Answer: (C) Iodine
Solution: Iodine, though it is a non-metal, has a property of having a shiny surface. Therefore showing the property of luster, like a metal.
40. Sodium metal is dipped in which of the following substances for storage?
D. sulphuric acid
Answer: (B) kerosene
Solution: Sodium metal is very reactive. It reacts vigorously with oxygen and water. A lot of heat is generated in the reaction. It is, therefore, stored in kerosene
41. Which of the following order is correct for the reactivity of metals?
A. Na > Au > Fe > Mg
B. Na > Mg > Fe > Au
C. Mg > Fe > Na > Au
D. Mg > Na > Fe > Au
Answer: (B) Na > Mg > Fe > Au
Solution: Sodium (Na) is the most reactive element amongst the other three because sodium reacts violently even with the cold water. Magnesium (Mg) on the other hand, reacts to a very little extent to the warm water. Red hot iron (Fe) reacts with steam at high temperature. And lastly, gold (Au) is a noble metal, it barely reacts with the steam also.