NCERT Class X Science Class: Chapter –3. Metals and Nonmetals– Part-11

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Question 62:

  1. Given below are the steps for extraction of copper from its ore. Write the reaction involved.

    1. Roasting of copper (I) sulphide

    2. Reduction of copper (I) oxide with copper (I) sulphide

    3. Electrolytic refining

  2. Draw a neat and well labelled diagram for electrolytic refining of copper

Answer:

  1. Roasting of sulphide ore:

    1. This reaction is known as auto-reduction

    2. Reaction for electrolytic refining

  2. Diagram for electrolytic refining of copper:

Image electrolytic refining of copper

Image Electrolytic Refining of Copper

Image electrolytic refining of copper

Question 63:

Of the three metals X, Y and Z. X reacts with cold water, Y with hot water and Z with steam only. Identify X, Y and Z and also arrange them in order of increasing reactivity.

Answer:

  • X is alkali metal, .

  • It is a soft metal.

  • It can be cut with a knife.

  • It reacts vigorously with cold water.

  • Y is alkaline earth metal,

  • It reacts with hot water.

  • Z is

  • It does not react with hot or cold water but reacts only with steam.

Therefore,

Increasing reactivity series:

Question 64:

An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give a product C. An aqueous solution of product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D. Also write down the equations for the reactions involved.

Answer:

A is sodium because it burns with golden flame in air. B is chlorine as its atomic number is 17. When Na reacts with , is formed. Hence, C is sodium chloride

Aqueous solution of , on electrolysis gives sodium hydroxide. Thus, D is sodium hydroxide

Question 65:

Two ores A and B were taken. On heating ore gives whereas, ore B gives . What steps will you take to convert them into metals?

Answer:

Since ore gives and ore B gives . Therefore, ores are

As, A is a carbonate ore, it is first subjected to calcination followed by reduction.

As B is a sulphide ore, it is first subjected to roasting followed by reduction.

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