NCERT Class X Science Solutions: Chapter 3 – Metals and Non-Metals Part 2

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Question 7:

Name two metals which will displace hydrogen from dilute acids, and two metals which will not.

Answer:

Metals that are more reactive than hydrogen displace it from dilute acids.

For example: sodium and potassium.

Metals that are less reactive than hydrogen do not displace it.

For example: copper and silver.

Question 8:

In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?

Answer:

In the electrolytic refining of a metal M:

Anode → impure metal M

Cathode → thin strip of pure metal M

Electrolyte → Solution of salt of the metal M

Question 9:

Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.

Image result for Pratyush took sulphur powder on a spatula a …

Collecting Gas in Test Tube

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  1. What will be the action of gas on?

  2. Dry litmus paper?

  3. Moist litmus paper?

  4. Write a balanced chemical equation for the reaction taking place.

Answer:

  1. There will be no action on dry litmus paper.

  2. Since the gas is sulphur dioxide (), it turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid.

B.

Question 10:

State two ways to prevent the rusting of iron.

Answer:

Two ways to prevent the rusting of iron are:

Oiling, greasing, or painting:

By applying oil, grease, or paint, the surface becomes water proof and the moisture and oxygen present in the air cannot come into direct contact with iron. Hence, rusting is prevented.

Galvanization:

An iron article is coated with a layer of zinc metal, which prevents the iron to come in contact with oxygen and moisture. Hence, rusting is prevented.

Question 11:

What type of oxides is formed when non-metals combine with oxygen?

Answer:

Non-metals combine with oxygen to form acidic oxides.

For example: