Free download NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals in PDF form. Class X Science all chapters solutions are in the same form to free download.
NCERT Solutions for Class 10 Science Chapter 3
Important Questions from CBSE Board Papers
Class X Chemistry – Metals and Non – Metals
Why are aluminium and copper metals used for making cooking vessels?
Aluminium and copper metals are good conductor of heat. When exposed to air, these develop a layer of oxide. This makes it resistant to further corrosion.
Compare the properties of a typical metal and non-metal on the basis of the following:
(i) nature of oxide formed by them
(i) Metals from basic oxide, e.g., sodium gives a basic oxide, Na_2 O. Non-metals from acidic oxide, e.g., sulphur gives an acidic oxide, SO_2.
(ii) Metals have good conductivity, e.g., copper is a good conductor. Non-metals do not conduct heat or electricity, e.g., sulphur.
Explain, why some metals are more reactive and others less reactive and others less reactive?
What determines the reactivity of metals?
When metals react, they lose electrons to form positive ions. Such metals which can lose electrons easily to form positive ions when reacted with other substances, are reactive metals. On the other hand, if a metal loses electrons less rapidly to form positive ions, it will reacts slowly with other substances. Such a metal will be less reactive. For example, sodium atom is a very reactive metals because it readily loses one electron, forms a positive ion which then combines with other substances. On the other hand, lead atom loses electrons with difficulty to form positive ions, so lead metal is less reactive.
Why is sodium kept immersed in kerosene oil?
Sodium is very reactive. If kept exposed to air, it catches fire.
(i) Ionic compounds have high melting point.
(ii) Ionic compounds are hard crystalline solids.
(i) In iconic compounds, ions are joined together due to powerful electrostatic forces, therefore, considerable energy is required to separate these ions and break the lattice. Thus ionic compounds have high melting points.
(ii) There are solids due to strong force of attraction between oppositely charged ions resulting in the formation of hard crystalline lattice.
How is an ore different from a mineral?
“all ores are minerals but all minerals are not ores”. Justify the statement with examples.
The metals found in nature in combined state are called minerals. If some minerals contain a very high percentage of a particular metal and the metals can be profitably and economically extracted, then it is called an ore.
What are alloys?
An alloy is a homogeneous mixture of two or more metals, or a metals and a non-metal. It is prepared by first melting the main metal, and then dissolving the required amount of other metals or non-metals. This mixture is then cooled to form an alloy of a given composition.
Atmospheric air always contains moisture. Then, how can you protect iron articles from the affect of atmosphere?
Iron articles can be protected from the effect of atmosphere by painting, oiling and greasing. This gives temporary protection to iron articles. For long time protection, galvanising or chrome plating are quite useful.
What is meant by metallurgy?
Metallurgy involves various processes starting with the treatment of ore to getting metals in the pure form.
Distinguish between calcinations and roasting.
(i) The ore is heated is absence of air.
(ii) It is used for carbonate ores.
(i) The ore is heated in the presence of air.
(ii) It is used for sulphide ores.