NCERT Class 10 Chapter 5 Metals and Non Metals CBSE Board Sample Problems Short Answer (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question

Explain any three methods used for preventing Corrosion of metals?

Solution

Alloying: Mixing of the metal with another metal or non-metal can help in preventing Corrosion of metals.

Example:- alloying Iron with Carbon to form steel

Electroplating: Platting a layer of Chromium over the surface of metal can help in preventing metals from getting corroded.

Galvanization: Iron metal is dipped in molten zinc, which forms a layer of zinc over

Iron.

Question

Two Ores on Heating, A gives, whereas ore B gives. Explain the processes with help of balanced chemical equation, which is used to convert ores A and B into their oxide ores with an example.

Solution

Ore A is Carbonate Ore.

The process involved in converting ores

Calcination: The Carbonate ore is heated strongly in absence of air.

Ore B is sulphide ore.

The process involved in converting ores

Roasting: The suiphide ore is heated strongly in presence of excess of air, this is known as roasting.

Question

a) What are amphoteric oxides? Choose the amphoteric oxides from amongst the following oxides:

b) Why is it that non-metals do not displace hydrogen from dilute acids?

Solution

a) Amphoteric oxides are metal oxides which show both basic as well as acidic behaviour.

b) Non-metals cannot lose electrons to H + to form gas because nonmetals are electron-acceptors hence they do not react with dilute acids.

Question

What are amphoteric oxides? Choose the amphoteric oxides from the following:

Solution

The oxides which are acidic as well as basic in nature are called amphoteric oxides are amphoteric oxides.

Question

Explain the following:

Sodium chloride is an ionic compound which does not conduct electricity in solid state where as it does conduct electricity in molten state as well as in aqueous solution.

Reactivity of aluminium decrease if it is dipped in nitric acid.

Metals like calcium and magnesium are never found in their free state in nature.

Solution

a) In molten state, due to heat the electrostatic forces of attraction between the oppositely charged ions are overcome. So ions move freely and conduct electricity. In aqueous solution also ions are free and conduct electricity.

b) Due to the formation of a coating of aluminium oxide or

C) Reactive metals like calcium and magnesium react easily with different elements and occur in the form of ores.

Question

How mercury is extracted from its suiphide ore? Write the balanced chemical equations involved in the process.

Why are carbonate or sulphide ores converted to oxides during the process of extraction?

Is magnesium oxide an ionic compound or a covalent compound? Give reasons to support your answer.

Solution

1 . Cinnabar is heated in air; it is first converted into mercuric oxide () . Mercuric

Oxide is then further heated to be reduced to mercury.

2. Obtaining a metal from its oxide is much easier than doing that from a metal suiphide or carbonate. Due to this metal sulphides and carbonates are first converted to metal oxides.

3. it՚s an ionic compound. This compound is formed by transfer of electrons from magnesium to oxygen.

Question

is an amphoteric oxide. With the help of chemical equations, explain why is it called an amphoteric oxide?

Solution

Amphoteric oxides are he oxides which react both with acids and bases to produce salts and water.

Question

1 . Identify the reaction given below:

2. Identify the oxidizing and reducing agent in this reaction.

3. State an application of this reaction.

Solution

This is thermite reaction (displacement reaction)

Al is the reducing agent and is the oxidizing agent.

This reaction is highly exothermic and the metals are produced in molten state in these reaction so this reaction is used to join railway tracks or cracked machine parts.

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