Class 10 Science Chapter 3 MCQ

Hydrogen (H) is the non-metal element which loses electrons to form positive ions, hydrogen ions (H+).

Electrical wires have a coating of an insulting material called PVC (Polyvinylchloride). PVC is a polymer and bad conductor of electricity. It is the most common insulating material used to insulate electrical conductors from electric charge thus preventing human contact with live electricity. Graphite is good conductor of electricity. Hence it cannot be used as insulating material. Sulphur, although is a bad conductor of electricity, but is brittle in nature. So, cannot be used as insulating material.

The major non-metals in the earth’s crust in the decreasing order of their abundance are: Oxygen, Silicon, Phosphorus and Sulphur.

Compound Z does not show the property of “Has low melting point”. As compound Z is formed because of transfer of electrons between X and Y, hence Z is an ionic compound. Such compounds do not have low melting point. Bonds in ionic compounds are very strong. Therefore, a lot of energy is needed to break them. This is the reason why ionic compounds have high melting and boiling points.

Here, all statements are correct. Hence, your answer will be option [D].

The metals which have high densities, we mean that metals are heavy substances. For example, the density of iron is 7.8 g/cm3 which is quite high. So, iron metal is a heavy substance. There are, however, some exceptions. For example, sodium and potassium metals have low densities (of 0.97 g/cm3 and 0.86 g/cm3 respectively). They are very light metals.

Test tube C contains chemical mixture called aqua-regia. It is a mixture of concentrated HCl and concentrated HNO3 in the ratio of 3:1. Aqua-regia dissolves gold and platinum in it while hydrochloric acid and nitric acid do not.

Metals react with oxygen to form metal oxides. Metal oxides are basic in nature. Some of the metal oxides react with water to form alkalis. Metal oxides, being basic, turn red litmus solution blue.

A solution of sulphur dioxide in water turns blue litmus to red. This shows that sulphur dioxide is acidic in nature.

Iodine is a non-metal that is lustrous. Graphite is another non-metal that is shiny and lustrous.

Magnesium metal does not react with cold water. Magnesium reacts with hot water to form magnesium hydroxide and hydrogen: You can easily understand by this equation: Mg (s) + 2H2O (l) → Mg(OH)2 (aq) + H2 (g) Magnesium + Water (hot) → Magnesium hydroxide + Hydrogen

Alloying elements enhance the structure and properties such as durability, strength and toughness of the metal. It makes them corrosion resistant. Stainless steel is an alloy of iron, nickel and chromium.

Here, all the statements are correct. Hence, your answer will be option [D].

Nitrogen is an inert gaseous non-metal whose presence in air reduces the rate of combustion and makes it safe.

Gold (Au) and silver (Ag) are not reactive or very less reactive. These metals are called noble metals. Thus, these are placed at the bottom of the reactivity series. Since gold and silver are least reactive of all the metals, these are found in free state in nature.

In solid state, ions in ionic compounds are not free to move. Thus, such compounds do not show electrical conductivity in solid state. Whereas, in molten state, ions are free to move and hence conduct electricity.

Here, all the statements are correct. Hence, your answer will be option [D].

Non-ionic compounds are those that have covalent bonds. Hydrochloric acid (HCl) and carbon tetrachloride (CCl4) form covalent due to sharing of a pair of electrons between two atoms. Whereas sodium chloride (NaCl) and potassium chloride (KCl) form ionic compounds as they consist of positive and negative ions.

Aqua-regia is a mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1. Aqua-regia being a very strong acid dissolves gold in it.

Does not give hydrogen gas on reacting with metals. Nitric acid is a strong oxidizing agent. It oxidizes hydrogen produced in the reaction to water and nitric acid itself is reduced to any of these nitrogen oxides [N2O (nitrous oxide), NO (nitric oxide) or NO2 (nitrogen dioxide)]. On the contrary, magnesium and manganese reacts with dilute nitric acid to give salt and hydrogen gas.

When steam is passed over iron for a long time, it gives iron oxide (Fe3O4) and hydrogen gas. You can easily understand by this equation: 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g)

Carbon is a non-metal that can exist in different forms. Each form is called an allotrope. Diamond, an allotrope of carbon, is the hardest natural substance known and has a very high melting and boiling point. Note: Graphite, another allotrope of carbon, is a conductor of electricity.

Copper metal is more reactive than silver metal (Ag), so a displacement reaction will take place between AgNO3 solution and copper metal. In option A: Copper metal is less reactive than sodium metal (Na), so no displacement reaction will occur between NaCl solution and copper metal. In option B: Aluminium metal is less reactive than magnesium metal (Mg), so no displacement reaction will take place between MgCl2 solution and Aluminium metal. In option C: Silver metal is less reactive than iron metal (Fe), so no displacement reaction will occur between FeSO4 solution and silver metal.

Aluminium has good thermal conductivity and high melting point. As a good conductor of heat, it helps in heat transfer and cooking of food. With the high melting point, one can cook food in such utensils at higher temperatures and the Aluminium utensils can withstand such higher temperatures without being melted by the heat.

The ability of metals to be drawn into thin wire is called ductility. It is one such property of metals that is used to make wires from metals. Metals such as copper have high ductility and thus can be drawn into long and thin wires without breaking.