Class 10 Science Chapter 3 Practice Question Answers - Metals and Non-metals

Fill in the Blanks
Q1: The ability of metals to be drawn into thin wires is called _______________.
Ans: ductility

Q2: Non-metals generally have _______________ lustre.
Ans: no

Q3: The element that is an essential constituent of chlorophyll is _______________.
Ans: magnesium

Q4: The process of applying a thin layer of zinc on iron to prevent rusting is called _______________.
Ans: galvanization

Q5: _______________ is a soft metal used in making electric wires and cables.
Ans: Copper

Short Answer Questions
Q6: Differentiate between metals and non-metals based on their physical properties.
Ans: Metals are generally good conductors of heat and electricity, have a metallic lustre, and are malleable and ductile. Non-metals are poor conductors, lack lustre, and are brittle.

Q7: Why do ionic compounds generally have high melting and boiling points?
Ans: Ionic compounds consist of positive and negative ions held together by strong electrostatic forces. It requires a considerable amount of energy to overcome these forces, leading to high melting and boiling points.

Q8: Explain the process of rusting of iron with the help of a chemical reaction.
Ans: Rusting is the oxidation of iron in the presence of moisture and air, forming iron oxide. The chemical equation is: 4Fe + 3O2 + 6H2O -> 4Fe(OH)3. This process weakens the iron structure over time.

Q9: How does the reactivity of metals change as we move down the reactivity series?
Ans: The reactivity of metals increases as we move down the reactivity series. Metals at the top are less reactive and lose electrons easily, while those at the bottom are highly reactive and tend to gain electrons.

Q10: Why is sodium kept immersed in kerosene oil?
Ans: Sodium is highly reactive and reacts vigorously with air and moisture. Keeping it immersed in kerosene oil prevents its contact with air and moisture, thus preventing rapid oxidation.

Long Answer Questions
Q11: Explain the process of electrolytic refining of copper.
Ans: Electrolytic refining is used to purify impure copper. Impure copper is made the anode and a thin sheet of pure copper is made the cathode in an electrolytic cell filled with a copper sulfate solution. When electricity is passed through the cell, copper from the anode dissolves and gets deposited on the cathode as pure copper. Impurities settle at the bottom as anode mud.

Q12: Compare the properties of metals and non-metals in terms of their chemical reactivity.
Ans: Metals readily lose electrons to form positive ions (cations) and are good reducing agents. Non-metals, on the other hand, tend to gain electrons to form negative ions (anions) and are good oxidizing agents. Metals react with acids to liberate hydrogen gas, while non-metals do not show this behavior.

Q13: Describe the extraction of iron from its ore, haematite, using a blast furnace.
Ans: In a blast furnace, haematite (iron ore) is mixed with coke (carbon) and limestone (flux). The mixture is heated at high temperatures, and carbon monoxide reduces haematite to iron. The iron melts and collects at the bottom, forming pig iron. The impurities react with limestone to form slag, which floats on top and is removed.

Q14: Why do ionic compounds conduct electricity in molten state or aqueous solutions but not in solid state?
Ans: In the solid state, ions in ionic compounds are held in a fixed position and cannot move. However, in the molten state or in aqueous solutions, the ions are free to move and can carry an electric current. This is because the movement of ions is necessary for electrical conduction.

Q15: Discuss the uses of metals and non-metals in daily life with suitable examples.
Ans: Metals like iron are used in construction, aluminum in making utensils, and copper in electrical wiring. Non-metals like sulfur are used in making matches, carbon in pencils, and oxygen in respiration. Non-metal helium is used in filling balloons due to its low density.