Class 10 NCERT Solutions Metals and Non-metals - NCERT Solutions prepared for CBSE students by the best teachers in Delhi.
Metals and Non-metals
Question 1: Explain the meanings of malleable and ductile.
Answer: Malleable: Substances that can be beaten into thin sheets are called malleable. For example, most of the metals are malleable.
Ductile: Substances that can be drawn into thin wires are called ductile. For example, most of the metals are ductile.
Question 2: Why is sodium kept immersed in kerosene oil?
Answer: Sodium and potassium are very reactive metals and and combine explosively with air as well as water. Hence, they catch fire if kept in open. Therefore, to prevent accidental fires and accidents, sodium is stored immersed in kerosene oil.
Question 3: Write equations for the reactions of
(i) iron with steam
(ii) calcium and potassium with water
Question 4: Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows. MetalIron (II) sulphateCooper (II) sulphateZinc sulphate Silver nitrate
A. No reaction Displacement
B. Displacement No reaction
C. No reaction No reaction No reaction Displacement
D. No reaction No reaction No reaction No reaction Use the Table above to answer the following questions about metals A, B, C and D.
(i) Which is the most reactive metal?
(ii) What would you observe if B is added to a solution of copper (II) sulphate?
(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.
A + FeSO4 ¨ No reaction, i.e., A is less reactive than iron
A + CuSO4 ¨Displacement, i.e., A is more reactive than copper
B + FeSO4 ¨ Displacement, i.e., B is more reactive than iron
B + ZnSO4 ¨No reaction, i.e., B is less reactive than zinc
C + FeSO4 ¨ No reaction, i.e., C is less reactive than iron
C + CuSO4 ¨No reaction, i.e., C is less reactive than copper
C + ZnSO4 ¨No reaction, i.e., C is less reactive than zinc
C + AgNO3 ¨ Displacement, i.e., C is more reactive than silver
D + FeSO4/CuSO4/ZnSO4/AgNO3 ¨No reaction, i.e., D is less reactive than iron, copper, zinc, and silver
Question 5: Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
Answer: Hydrogen gas is evolved when dilute hydrochloric acid is added to a reactive metal. When iron reacts with dilute H2SO4, iron (II) sulphate with the evolution of hydrogen gas is formed.
Question 6: What would you observe when zinc is added to a solution of iron (II) sulphate?Write the chemical reaction that takes place.
Answer: Zinc is more reactive than iron. Therefore, if zinc is added to a solution of iron (II) sulphate, then it would displace iron from the solution.
Question 7: (i) Write the electron-dot structures for sodium, oxygen and magnesium.
(ii) Show the formation of Na2O and MgO by the transfer of electrons.
(iii) What are the ions present in these compounds?
Answer: (i) The representation of elements with valence electrons as dots around the elements is referred to as electron-dot structure for elements.
Question 8: Why do ionic compounds have high melting points?
Answer: Ionic compounds have strong electrostatic forces of attraction between the ions. Therefore, it requires a lot of energy to overcome these forces. That is why ionic compounds have high melting points.
Question 9: Define the following terms.
(i) Mineral (ii) Ore (iii) Gangue
Answer: (i) Mineral: Most of the elements occur in nature as in combined state as minerals. The chemical composition of minerals is fixed.
(ii) Ore: Minerals from which metals can be extracted profitably are known as ores.
(iii) Gangue: The impurities (sand, silt, soil, gravel, etc.) present in the ore are called gangue.
Question 10: Name two metals which are found in nature in the free state. The metals at the bottom of the reactivity series are mostly found in free state. For example: gold, silver, and platinum.
Question 11: What chemical process is used for obtaining a metal from its oxide?
Answer: The chemical process used for obtaining a metal from its oxide is reduction. In this process, metal oxides are reduced by using suitable reducing agents such as carbon or by highly reactive metals to displace the metals from their oxides.
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