Class 10 Science Chapter 3 MCQ

Bromine, a non-metal, is a liquid. Metals are generally solid whereas non-metals can be solid, liquid and gas. Bromine is a non-metal that exists as liquid.

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

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

Silver metal is the best conductor of heat. Copper and Aluminium metals are also very good conductors of heat. Mercury metal is also a poor conductor of heat. The poorest conductor of heat among the metals is lead.

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

Ag (silver) would be displaced from the solution of its salts by other three metals, i.e., magnesium (Mg), zinc (Zn) and copper (Cu). Silver (Ag) is a noble metal and is least reactive metal among other metals given.

Sodium and calcium are very reactive metals and are placed towards the top of the reactivity series. These are produced by the electrolysis of their molten chlorides. The metal ions are deposited at negatively charged cathode and chlorine is deposited at positively charged anode.

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

Mercury (Hg) is the only metal which is found in liquid state at room temperature. All other metals are solid at room temperature. It also has the lowest melting point.

Potassium reacts violently with cold water to form potassium hydroxide and hydrogen gas: You can easily understand by this equation: 2K (s) + 2H2O (l) → 2KOH (aq) + H2 (g) + Heat Potassium + Water(cold) → Potassium hydroxide + Hydrogen The reaction of potassium metal with water is highly exothermic (heat producing) due to which the hydrogen gas formed during the reaction catches fire immediately. Thus, potassium is a very, very reactive metal.

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

Oxygen (O) is a non-metal which forms negatively charged oxide ions (O2–) by gaining electrons.

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

Gold (Ag) and copper (Cu) obtained after extraction is in impure form. So, metals Au (gold) and Cu (copper) are refined by electrolytic refining. Other than gold and copper, electrolytic refining is used for metals such as Zn and Ag. Sodium (Na) and potassium (K) are extracted by electrolytic reduction. Metals obtained after electrolytic reduction are in pure form.

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.

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.

Pure gold, known as 24 carat gold, is very soft. It is, therefore, not suitable for making jewellery. It is alloyed with either silver or copper to make it hard. Generally, in India, 22 carat gold is used for making ornaments. It means that 22 parts of pure gold is alloyed with 2 parts of either copper or silver.

When calcium is treated with water, it reacts with water vigorously and to produce a cloudy white precipitate of calcium hydroxide and hydrogen gas is released as bubbles. You can easily understand by this equation: Ca(s) + 2 H2O(g) → Ca(OH)2(s) + H2(g) Sometimes hydrogen bubbles get stuck to the surface of calcium metal making it light and thus calcium starts floating. This reaction is exothermic in nature.

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.

Na (sodium) and Ca(calcium) react with water vigorously. Mg (Magnesium) reacts with water less vigorously than that of calcium and sodium. Fe (Iron), on the other hand, does not react with cold as well as hot water instantly. But when the iron is kept in contact with water for a long time, rusting of iron happens.

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.

If a metal is below hydrogen in the activity series, then it will not displace hydrogen from water and acids, that is, it will not react with water and acids to produce hydrogen gas. We should remember the reactivity series of metals to decide whether a particular displacement reaction will take place or not.

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.