# CBSE Solutions for Class 10 Maths

#### Select CBSE Solutions for class 10 Subject & Chapters Wise :

Non-metals are ……………. in character.

The chlorides of non-metals are …………….

covalent

A sulphide ore is concentrated by …………….

Oxides of non-metals when dissolved in water generally give ……………. solutions.

acidic

Removal of impurities from a metal by chemical method is called …………….

leaching

……………. displaces copper from a solution of copper (II) sulphate.

Zinc

Metal have ……………. melting and boiling points.

high

The process in which the concentrated ore is heated below its melting point in the absence or limited supply of air is called …………….

Calcination

Metal oxides ……… and ……… dissolve in water to form alkalis.

Sodium Oxide and Potassium oxide

Metals which are so soft that they can be cut with a knife are ………, ………

Sodium, Potassium

……… is an allotroph of carbon and is the hardest natural substance.

Diamond

The extraction of metals from their ores and then refining them for use is known as ……… .

metallurgy

Metals above hydrogen in the activity series can displace ……… from dilute acids.

Hydrogen

A metal which burns in air with a dazzling white flame is ……… .

Magnesium

A non-metal which is lustrous is ……… .

Iodine

Metals can form positive ions by ……… .

losing electrons

A non-metal which is a good conductor of electricity is ……… .

Graphite

Two metals which melt when kept on the palm are ………, ……… .

Gallium, Caesium

Two metals which melt when kept on the palm are ………, ……… .

Gallium, Caesium

Elements can be classified as ……… and ……. .

metals, non-metals

(a) what's the activity series of metals ? Arrange the metals Zn, Mg, Al, Cu and Fe during a decreasing order of reactivity.
(b) What would you observe once you put
1. some zinc pieces into blue copper sulfate solution ?
2. some copper pieces into green ferrous sulphate solution ?
(c) Name a metal which mixes with hydrogen gas. Name the compound formed.

(a) we discover that zinc occupies a way higher position within the acitivity series as compared to copper. it's expected to displace copper present within the solution of its salt (e.g. CuSO4).

(b)

1. Blue colour of copper sulphate solution would slowly disappear.
2. No change would be noticed.

(c) Sodium combines with hydrogen to form sodium hydride.

(a) Why is ZnO called an atmospheric oxide? Name another atmospheric oxide?
(b) Whar are alkalies? Give one exampleof alkalies?

(a)

Aluminium oxide (Al2O3) is another amphoteric oxide.
(b) Water soluble hydroxides of metals are known as alkalis. For example, NaOH.

Give reasons for the subsequent :
Metals replace hydrogen from dilute acids whereas non-metals don't .

Metals are electropositive in nature. Their atoms readily lose electrons to make positive ions. The electrons are accepted by H+ ions of the acid to evolve hydrogen gas. for instance ,
Zn(s) ———-> Zn2+(aq) + 2e– ;
2H+(aq) + 2e– ————> H2(g)
Non-metals are electronegative in nature. this suggests that their atoms can take up electrons and can't lose them. Therefore, they are doing not evolve hydrogen on reacting with dilute acids.

Name an ore of zinc aside from flowers of zinc . By which process can this ore be converted into flowers of zinc ?

The ore of zinc aside from flowers of zinc (zincite) is zinc carbonate (calamine). it's the formula ZnCO3 Calamine is converted into flowers of zinc by calcination i.e., by heating strongly within the absence of air.

Which method of concentration of ore is preferred within the following cases and why ?
1. The ore has higher density particles mixed with an outsized bulk of rarity impurities.
2. The ore consists of copper sulphide intermixed with clay particles.
Give an example of amalgam.

1. The concentration of ore are often done by gravity separation method.
2. The concentration of ore is completed by Froth Floatation process.
An amalgam of mercury with silver or gold called dental alloy is employed to fill cavities within the teeth.

On placing a bit of zinc metal during a solution of mercury chloride , it acquires a silvery surface but when it's placed during a solution of magnesium sulphate, no change is observed. State the rationale for the behaviour of zinc metal.

Zinc lies above mercury within the activity series and may easily replace it from mercury chloride solution. Mercury formed within the reaction gets deposited on the surface of zinc to offer it a silvery look.

But zinc is placed below magnesium in the activity series. Therefore, no chemical reaction occurs between zinc and magnesium sulphate solution.

A copper plate was dipped into an answer of AgNO3. After sometime, a black layer was deposited on the copper plate. State the rationale for it. Write the chemical equation for the reaction involved.

Copper lies above silver within the activity series. this suggests that copper is more reactive than silver. Therefore, copper had replaced silver from AgNO3 solution. Silver got deposited on the copper plate and altered to black after sometime because silver and also some salts of silver are sensitive to light. They readily become blackish on standing or on exposure to air.

Why is titanium is called as a strategic metal? Mention two of its properties which make it so special.

Titanium is called strategic metal because it is used for making certain war equipments. The properties which make the metal so special are :

1. It is light in weight but at the same time stronger than the other metals.
2. It is not affected by corrosion even if kept in the open for a very long time.

(a) An iron knife kept in blue copper sulfate solution turns the blue solution into light green. Explain.
(b) An athlete won a trophy during a race competition. After some days, he found that the medal had lost its lustre thanks to the formation of a greenish layer thereon . Name the metals present within the medal. what's the rationale for the looks of a greenish layer on its surface ?

(a) Iron lies above copper within the activity series. this suggests that iron or iron knife will displace copper from copper sulfate solution. As a results of the reaction, ferrous sulphate are going to be formed and therefore the solution are going to be light green in colour.

(b) The bronze medal is an alloy and the constituting metals are copper and tin.
The loss of lustre by the medal is due to the formation of a coating of green layer. This layer is at basic copper carbonate.

“All ores are minerals but all minerals are not ores”. Give explanation for the statement.

In the earth’s crust, metals are present within the sort of minerals and there are quite one mineral for a specific metal. However, metal might not be extracted from all of them. The mineral from which a metal are often profitably and conveniently extracted is understood as ore. This clearly means all ores are minerals but all minerals aren't ores. for instance the various minerals of iron are :
Haematite : Fe2O3 ;
Limonite : Fe2O3.3H2O;
Siderite : FeCO3 ;
Iron pyrites : FeS2
Iron is extracted from haematite (Fe2CO3). Haematite mineral is that the ore of iron while other minerals aren't the ores.

 Metal which melt if you keep them on your palm Ore Metal which melt if you keep them on your palm Sodium Substance from which metal can be extracted by metallurgy Caesium Metal which can be cut with knife Corrosion

Caesium
Corrosion
Ore
Sodium

 A homogeneous mixture of two or more metals . Brass An alloy of copper and zinc Iodine Property of metal due to which metal produce a sound on striking a hard surface Alloy Lustrous non-metal Sonorous

Alloy

Brass

Sonorous
Iodine