Give reasons
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
(a) Platinum, gold, and silver are used to make jewellery because they are very lustrous as well as they are very less reactive and do not corrode easily.
(b) Sodium, potassium, and lithium are very reactive metals and react very vigorously with air and water. So, they are kept in kerosene oil in a way to prevent their direct contact with air and moisture.
(c) Aluminium is a reactive metal, yet it can resistant to corrosion. This is because aluminium reacts with oxygen present in air to form aluminium oxide. This oxide layer is quite stable and which further prevents reaction of aluminium with oxygen. Also, it is lightweight and a good conductor of heat. Therefore why it is used to make cooking utensils.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction because metals can be more easily extracted from their oxides than from their carbonates and sulphides.
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This question is important because it tests key concepts from the NCERT syllabus and is frequently asked in CBSE exams.
This question is based on core NCERT concepts explained in the chapter and should be revised thoroughly before exams.
(a) Platinum, gold, and silver are used to make jewellery because they are very lustrous as well as they are very less reactive and do not corrode easily.
(b) Sodium, potassium, and lithium are very reactive metals an...
Step-by-step explanation:
• (a) Platinum, gold, and silver are used to make jewellery because they are very lustrous as well as they are very less reactive and do not corrode easily
•
•
• (b) Sodium, potassium, and lithium are very reactive metals and react very vigorously with air and water
• So, they are kept in kerosene oil in a way to prevent their direct contact with air and moisture
Students often lose marks by skipping steps, writing incomplete explanations, or misunderstanding keywords used in the question.
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