Metals and Non Metals MCQ

Answer - C) Fe₃O₄

Explanation - Prolonged reaction of iron with steam leads to the formation of magnetite (Fe₃O₄), which is a mixed oxide of iron containing both Fe²⁺ and Fe³⁺ ions. The reaction between iron and steam is exothermic and leads to the oxidation of iron to form Fe₃O₄. Fe₃O₄ is a magnetic compound and is commonly found in nature as a black mineral.

Answer - C) 1 - 1

Explanation - Aqua regia is a highly corrosive mixture of concentrated nitric acid (HNO₃) and concentrated hydrochloric acid (HCl) in a 1 - 1 ratio. This mixture is commonly used in the laboratory for the extraction of noble metals, such as gold and platinum, due to its ability to dissolve them. However, its corrosive nature makes it extremely dangerous and should be handled with caution.

Answer - C) Cinnabar to convert it into mercuric oxide and then heating it again

Explanation - Cinnabar, the ore of mercury, is first converted into mercuric oxide by roasting the ore in the air. The mercuric oxide is then heated to produce mercury vapor, which can be condensed and collected. Option C) accurately describes this process, making it the correct answer. 

Options A), B) and D) are incorrect as they describe the conversion of cinnabar into different compounds, not the correct one.

Answer - C) Hydrogen gas gets oxidised by HNO₃ to form water

Explanation - The first chemical equation shows that copper reacts with nitric acid to form copper nitrate Cu(NO₃)₂ and hydrogen gas (H₂). The second equation shows that hydrogen gas reacts with nitric acid to form water (H₂O) and nitrogen dioxide (NO₂). This means that hydrogen gas is getting oxidised (losing electrons) by nitric acid to form water. Hence, Option C is correct.

Answer - A) It catches fire and forms hydroxide

Explanation - When sodium is dropped in water, it reacts exothermically with the water to form sodium hydroxide (NaOH) and hydrogen gas (H₂). This reaction also releases a lot of heat, causing the sodium to catch fire and burn brightly. This reaction is highly dangerous, as the hydrogen gas produced can explode if it accumulates in a confined space.

Answer - C) Magnesium and calcium

Explanation - Magnesium and calcium are light metals and are less dense than water. When they are placed in water, they float because their density is less than the density of water. On the other hand, copper, silver, iron, zinc, aluminum, and lead are heavy metals and sink when placed in water because their density is greater than the density of water.

Answer - A) Tin > Lead > Copper > Mercury

Explanation - The reactivity series is a list of metals in order of their reactivity, based on how easily they can lose electrons. The most reactive metal is placed at the top, while the least reactive metal is placed at the bottom. The arrangement of Copper, Tin, Lead, and Mercury according to the reactivity series is Tin > Lead > Copper > Mercury, with Tin being the most reactive and Mercury being the least reactive. This means that Tin is more likely to lose electrons and react with other substances than Lead, Copper or Mercury.

Answer - B) They can share electrons with chlorine

Explanation - Non-metals are chemically reactive elements that do not conduct electricity well. They form covalent bonds with other atoms by sharing electrons, rather than transferring or accepting electrons. In the case of covalent chlorides, non-metals form a covalent bond with chlorine by sharing electrons, forming a molecule where the chlorine and non-metal atoms share electrons. This type of bond results in a stable molecule, which is why non-metals form covalent chlorides.

Answer - B. Nitrogen

Explanation - Nitrogen is a non-metal gas that is commonly used as a food preservative because it displaces the oxygen in food packaging, creating an environment that is not conducive to bacterial growth. This helps to slow down the spoilage of food and extends its shelf life. Nitrogen is an ideal choice for food preservation because it is an inert gas, meaning it does not react with other substances, and it is abundant and easily accessible.

Answer - A. Ca(OH)₂

Explanation - When calcium oxide (CaO) is added to water (H₂O), a chemical reaction takes place where the calcium oxide dissolves in water to form calcium hydroxide Ca(OH)₂. This reaction can be represented as -

CaO + H₂O → Ca(OH)₂

• Option A, Ca(OH)₂, is the correct answer as it represents the product formed in this reaction. 
• Option B, CaCO₃, is incorrect as calcium carbonate is not formed in this reaction. 
• Option C, Ca(H₂O)₂, is also incorrect as it is not a valid chemical compound. 
• Option D, CaO₂, is incorrect as it is not a product formed in this reaction.

Answer - A. Mercury and silver

Explanation - Amalgam is a mixture of two or more metals, in which the main component is mercury. The other metal in the alloy is typically silver, which is added to increase the hardness and durability of the amalgam. This mixture has a long history of use in dentistry and other applications where it is desired to join two metal objects together. Amalgams are also used in the production of certain industrial products and for electrical conductivity. The combination of mercury and silver forms a homogenous mixture, which is often called an amalgam.

Answer - B) Aluminum

Explanation - Metals are good conductors of heat and electricity and have a shiny appearance. 

• They are ductile and malleable, meaning they can be easily shaped and moulded. 
• Aluminum is a metal, while chlorine, carbon and sodium are non-metals.

Answer - C) A substance that is dull and does not conduct electricity well

Explanation - Non-metals are dull in appearance and are poor conductors of electricity and heat. 

• They are typically brittle and not malleable. 
• Non-metals, such as sulfur and carbon, are not flammable and typically have low melting and boiling points.

Answer - D) Shiny appearance

Explanation - Metals are typically characterized by their shiny appearance, which is a result of their reflective surface. 

• They are good conductors of heat and electricity and have high melting and boiling points. 
• They are ductile and malleable, meaning they can be easily shaped and moulded.

Answer - C) Silicon

Explanation - The majority of electronic devices, including TV, are made using semiconductors, materials that have electrical conductivity between that of a conductor and an insulator. 

• Silicon (Si) is the most common material used as a semiconductor in the electronics industry due to its stability, low cost, and abundance in nature. 
• In a TV, silicon is used to make the transistors and integrated circuits, which control the flow of electricity and regulate the functioning of the device. 
• Thus, the correct answer is option C - Silicon.