GK
ELEMENTS COMPOUNDS SUBSTANCES METALS AND NON METALS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Iron
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Coal
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Wood
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Oxygen
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Detailed explanation-1: -Out of the given options diamond is the hardest substance. It is one of the hardest materials on the Earth.
Detailed explanation-2: -Because of its low melting point, it is used in pipes and machines. We can now conclude that cast iron is very hard and brittle because of higher carbon content. Iron obtained from the blast surface is known as pig iron. The carbon content of wrought iron is the least.
Detailed explanation-3: -For example, Sodium being an alkali metal is very soft and can cut through a knife while iron which is a transition metal which is very hard and requires great energy to break apart. Iron is hard, tough and strong compared to sodium because of the strong metallic atom-atom bonding.
Detailed explanation-4: -It is because coal is a soft material while the iron is a hard, convincing, and cheapest material. The tools manufactured from hard materials are sustainable and durable. On the contrary, coal is a combustible rock and not a hard metal, and therefore it is an unconvincing and brittle material.