(English Medium) ICSE Class 10 - CISCE Important Questions for Chemistry

Arrange the following according to the instruction given in bracket:

Cu²⁺, Na⁺, Zn²⁺, Ag⁺ (The order of Preferential discharge at the cathode)

Electroplating steel objects with silver involves a three-step process.

Step 1: A coating of copper is applied to the object.

Step 2: A coating of nickel is applied to the object.

Step 3: The coating of silver is applied to the object.

1. 1. A diagram of the apparatus used for step 1 is shown
      
      
      1. The chemical process taking place on the surface of the object is \[\ce{Cu^2+(aq) + 2e- ->Cu(s)}\]
         What is the observation seen on the surface of the object?
      2. Explain why the concentration of copper ions in the electrolyte remains constant throughout step 1.
2. Give two changes which would be needed in order to coat nickel on to the object in step 2.
3. Write down the reaction taking place at the positive electrode during step 3.

Give a reason for Alkali metals are good reducing agents.

Name an alloy of lead and tin.

 Match the alloys given in column I to the uses given in column II : 

X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information, complete the following:

______ is the metallic element.

X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information, complete the following:

Metal atoms tend to have a maximum of ______ electrons in the outermost shell.

X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information, complete the following:

______ is the reducing agent.

Name the following:

A metal oxide that can be reduced by hydrogen.

Complete the following by selecting the correct option from the choices given:

The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction ____________. (Fe/Mg/Pb/Al)

Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.

Give appropriate scientific reasons for Zinc oxide can be reduced to zinc metal by using
carbon, but aluminium oxide cannot be reduced by a reducing agent

An element L consists of molecules.

When L is heated with iron metal, it forms a compound FeL. What chemical term would you use to describe the change undergone by L?

Write a balanced chemical equation for each of the following reactions :
(i) Reduction of copper (II) oxide by hydrogen

Identify the terms for the following:

The electrode where reduction takes place.

Answer the following question with reference to the electrorefining of copper:

What is the anode made of?

Answer the following question with reference to the electrorefining of copper:

What do you observe at the cathode?

Answer the following questions with reference to the electrorefining of copper:

Write the reaction taking place at the cathode.

The following sketch represents the electroplating of an Iron cup with Nickel metal.

Study the diagram and answer the following questions:

1. During electroplating, the iron cup is placed at the cathode. Why?
2. Name the ion that must be present in the electrolyte.
3. State one condition that is necessary to ensure that the deposit is smooth, firm and even.
4. Write the reaction taking place at the cathode.
5. What change would you observe at the anode?

The process of heating the concentrated ore in a limited supply or absence of air is ______.