Science Question Answer (3 Marks)

Copper cannot displace iron from iron sulphate solution. Copper is less reactive than iron. Iron is placed above the copper in reactivity series of metals. Therefore, copper cannot displace iron from iron sulphate solution. But if we put Iron nail into copper sulphate solution. Iron nail will displace copper from copper sulphate solution.

Aluminium is highly malleable and ductile. Due to this property, aluminium is used in the production of utensils and wire. Aluminium is a good conductor of heat which makes it ideal for making utensils.

The box made of metal can be identified by striking hard on its surface. Metals are sonorous because they produce a unique sound when something hard strikes their surface. The box which is made of metal will produce a sound on striking its surface.

1. Iron is used for making machinery and heavy equipment.
2. The copper is used in making electric wires because it is a good conductor of electricity.
3. Aluminium is used to make thin foils for packaging medicines, chocolates and food items. This is because it provides a complete barrier to light, oxygen, moisture and bacteria.
4. Zinc is widely used in the manufacture of many products such as paints, rubber, cosmetics, pharmaceuticals, plastics, inks, soaps, batteries, textiles and electrical equipment.
5. Mercury is used for making thermometers. It is liquid at room temperature and is a very good conductor of heat. Even a slightest change in temperature can be noted by using mercury.

Screwdriver is made of metal which is a good conductor of electricity. In order to prevent electric shocks by the screw driver its handle is made of wood. Wood is a poor conductor of electricity which protects from electric shocks and makes the screw driver safe from electric shocks.

Copper, gold and silver are Malleable and ductile because these are metals. The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling. The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. All of these metals can be used to make wires and sheets.
Sulphur, phosphorous and carbon are brittle. These are nonmetals and cannot be rolled into wires or drawn into sheets.

The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling.
The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. For example, Aluminium and copper are examples of highly ductile metals.
Metals have free electrons which makes them good conductors of heat and electricity. Non-metals do not have free electrons; hence, they are nonconductors of heat and electricity.

S.No	Properties	Metals	Nonmetals
1.	Malleability	Metals are highly malleable.	Nonmetals do not have malleability.
2.	Ductility	Metals are highly ductile.	Nonmetals do not have ductility.
3.	Conduction of heat and electricity	Good conductors of heat and electricity.	Poor conductors of heat and electricity.

The two physical properties on the basis of which metals can be distinguished from non-metals are Malleability and Ductility.
The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling.
The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. For example, Aluminum and copper are examples of highly ductile metals.

1. Carbon and Sulphur will form acidic oxides. Nonmetals react with oxygen to form nonmetallic oxides. These oxides differ from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Therefore, oxides of sulphur and carbon i.e. sulphur dioxide and carbon dioxide are acidic in nature.
2. Sodium and magnesium oxides will be basic in nature. Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases.

When a strip of zinc is placed in copper sulphate solution it will displace copper from copper sulphate solution. Zinc is placed above copper in reactivity series of metal. Hence, it will be able to replace copper from copper sulphate solution.
Zinc + Copper Sulphate → Copper + Zinc sulphate

1. Magnesium oxide

Magnesium is a metal. Metals react with oxygen to form metallic oxides. These Hence, Magnesium oxides are basic in nature. On the other hand, nonmetals react with oxygen to form nonmetallic oxides. These oxides differ from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Therefore, Sulphur dioxide is acidic in nature. Magnesium oxide is basic in nature.

It is difficult to hold a metallic pan without a plastic or wooden handle. This is because it will result into burning of fingers or hand due to high heat. If the metallic pan has a wooden handle, it will help to hold it. Wood is made of nonmetal which is a poor conductor of heat. Hence, wooden handle is very useful in metallic pan.

Metals react with water to produce hydrogen gas. Sodium reacts with water to form sodium hydroxide and hydrogen gas. Similarly, potassium also reacts with water to potassium hydroxide and hydrogen gas. Both Sodium and potassium are highly reactive metals. They can even react with the moisture present in air. The reaction of sodium and potassium with water is highly exothermic in nature. It produces a lot of heat energy and this heat energy can cause the hydrogen gas produced during the reaction, to catch fire. In order to keep it safe, sodium and potassium are stored in kerosene.

1. Metals react with water to produce hydrogen gas. Sodium reacts with water to form sodium hydroxide and hydrogen gas. Sodium is a highly reactive metal. It even reacts with the moisture present in air. The reaction of sodium with water is highly exothermic in nature. It produces a lot of heat energy and this heat energy can cause the hydrogen gas produced during the reaction, to catch fire. In order to keep it safe, sodium metal is stored in kerosene.
2. Metals reacts with water to form metal hydroxides and hydrogen gas. These metallic hydroxides are basic. Sodium reacts with water to form sodium hydroxide and hydrogen gas. Sodium hydroxide is basic in nature.

Food stuff like orange juice, pickles, chutney and curd are acidic in nature. Iron and aluminium are highly reactive metals. If any of this stuff is stored in iron or aluminium container the acid inside these food stuffs will react with iron or aluminium to produce toxins. Hence, we cannot store foodstuffs like orange juice, pickles, chutney and curd not be kept in iron or aluminium containers.

Element A is a nonmetal. Since, it is soft and brittle in nature.
Element B is a metal because it is malleable and ductile and it also conducts electricity. The property of metals which allows metals to be hammered into thin sheets is called Malleability. Due this unique property, metals can be flattened into thin sheets by hammering and rolling. The property of metals which enables them to be drawn into wires is called Ductility. Due to this property metals can be stretched without breaking and drawn into thin wires. All of these metals can be used to make wires and sheets.

1. Oxygen is the nonmetal which is essential for maintaining life and is inhaled during breathing. Oxygen is brought into our lungs via breathing. It is then transported by red blood cells to the entire body to be used to produce energy.
2. It can be used to replace air which helps to reduce or eliminate oxidation of materials. It is also used to make fertilizers and explosives.
3. It is used for making fire crackers.
4. Chlorine is used in water purification process to make drinking water supply germfree. Chlorine kills pathogens such as bacteria and viruses by breaking the chemical bonds in their molecules.
5. Iodine is used to make purple colored solution which is applied on cuts and wounds as an antiseptic. It is used in the treatment and prevention of wound infection.