Science MCQ

Sulphur is a nonmetal. It cannot be drawn into wires or changed into sheets. It is very soft and hence, is brittle in nature.

Silver is less reactive than zinc, copper and magnesium. It is below all these metals in the reactivity series of metals.

Silver is least reactive will not produce hydrogen gas with sulphuric acid.

Copper cannot displace iron from iron sulphate solution because copper is less reactive than iron.

Copper corrodes by oxidation in which it reacts with oxygen in the air to form copper oxide. Copper oxide then combines with carbon dioxide to make copper carbonate, which gives it a green colour. This process is called corrosion of copper.

Carbon is a nonmetal. Nonmetals form oxides which are acidic in nature. Oxide of carbon is acidic.

Carbon is a nonmetal. Nonmetals form oxides which are acidic in nature. Oxide of carbon is acidic and hence, its aqueous solution will turn blue litmus to red.

Potassium is a metal. Metallic oxides are basic in nature.

Potassium reacts with water to potassium hydroxide and hydrogen gas. The reaction 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 potassium is stored in kerosene.

Zinc sulphate solution and calcium cannot undergo displacement reaction.
This is because zinc is more reactive than iron.
Hence, iron cannot displace zinc from zinc sulphate solution.

Silver is least reactive and is placed below all these metals in reactivity series of 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.

Zinc is metal and it can be beaten into thin sheets. The property of metals which allows metals to be hammered into thin sheets is called Malleability.

Calcium is the most reactive metal than copper, iron and magnesium. It lies above all of these metals in reactivity series.

Silicon is a metalloid. The elements whose properties are intermediate between the properties of metals and nonmetals are called Metalloids.

Mercury is used for making thermometers. It is liquid at room temperature and is a very good conductor of heat.

Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases. Sodium is a metal; its oxide will be basic in nature and it will turn red litmus solution to blue.

Sodium is stored in kerosene because it is highly reactive and it even reacts with moisture from air and catches fire.

Brittleness is not a characteristic property of Iron because it is a metal. Malleability, ductility, and sonorousness are the properties of metals.

When gold jewellery is sent for polishing, it loses weight. While polishing, the outer thin layer of gold which is dull is removed by treatment with a chemical. The chemical treatment of this layer causes a reduction in weight of gold ornaments. This leads to a slight loss in the weight of jewellery.

The aqueous solution of the oxide turns blue litmus paper red. This means the aqueous solution is acidic in nature. Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases. On the other hand, nonmetals react with oxygen to form nonmetallic oxides. These oxides are different from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Since, the aqueous solution of this oxide is acidic in nature, the element is a nonmetal. For example, Sulphur is a nonmetal. It will form an oxide called sulphur dioxide which is acidic in nature.

Turmeric is used as a natural indicator. Turmeric is yellow in colour. Turmeric paper turns into red when it is dipped into basic solution. Turmeric paper does not change its colour with acid. The aqueous solution of this oxide turns turmeric paper red. It indicates that the oxide is basic in nature. Metals react with oxygen to form metallic oxides. These metallic oxides are basic because they react with water to form bases. On the other hand, nonmetals react with oxygen to form nonmetallic oxides. These oxides are different from metallic oxides because they are acidic in nature. Nonmetallic oxides react with water to form acids. Hence, the element is a metal. For example, magnesium is a metal, it reacts with oxygen to magnesium oxide, which is basic in nature.