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.

Al (Aluminium) forms amphoteric oxides. An amphoteric oxide acts both as an acid and as a base.

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

Atomic number of X is 10, so this must be Ne (Neon), a noble or inert gas. This gas has octate configuration. Atomic number of Y is 2 + 8 + 7 = 17, so this must be chlorine (Cl). Chlorine is a non–metal. Non-metals have 5 to 7 electrons in their valence shell. Atomic number of Z is 2 + 8 + 2 = 12, so this must be Magnesium (Mg). Magnesium is a metal. Metals have 1 or 2 electrons in their valence shell.

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

Na (sodium) possesses all the above properties. It is too soft and can be cut with a knife. It is also very reactive and reacts with oxygen or moisture present in air and produce sodium hydroxide which is highly exothermic reaction producing a lot of heat. It also reacts with water vigorously and burns due to the formation of hydrogen gas. That is why sodium is stored in kerosene oil to prevent any reaction.

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.

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

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

Copper gets green coating due to the formation of a mixture of copper carbonate and copper hydroxide when it reacts with carbon dioxide gas and moisture present in air. This is called tarnishing of copper. You can easily understand by this equation: 2Cu + H2O + CO2 + O2 → Cu(OH)2 + CuCO3

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.

Some metals are chemically very reactive whereas others are less reactive or unreactive. For example, potassium and sodium react very, very rapidly with cold water, so they are very reactive metals. Zinc and iron react only with steam, so they are less reactive metals. On the other hand, copper and silver do not react even with steam, so they are quite unreactive metals. Silver and gold metals also do not react with dilute acids.

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.

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.

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

Aqua regia, (Latin for ‘royal water’) is a freshly prepared mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1. It can dissolve gold, even though neither of these acids can do so alone. Aqua regia is a highly corrosive, fuming liquid. It is one of the few reagents that is able to dissolve gold and platinum.

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.

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)

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.

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.

Metals generally do not show dullness. Metals such as gold and silver usually are shiny rather than dull.