Metals and Non-metals NCERT In Text Questions
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4
Answer: When a reactive metal reacts with dilute hydrochloric acid, hydrogen gas is produced. The chemical equation for reaction between iron and dilute hydrochloric acid is as follows:
Fe + H2SO4 ⇨ FeSO4 + H2
At the end of this reaction, ferrous sulphate and hydrogen gas are formed.
What would you observe when zinc is added to a solution of iron(II) sulphate? Write the chemical reaction that takes place.
Answer: Zinc displaces iron from iron (II) sulphate solution because zinc is more reactive than iron. This reaction can be shown by following equation:
Zn + FeSO4 ⇨ ZnSO4 + Fe
Write the electron-dot structures for sodium, oxygen and magnesium.
Answer: Electronic dot structure of Na(11)
Electronic dot structure of O (8):
Electronic dot structure of Mg (12):
Show the formation of Na2O and MgO by the transfer of electrons.
Answer: Electron dot structures of sodium oxide and magnesium oxide are as follows:
What are the ions present in these compounds?
Answer: In both the compounds; oxide ions are present. Sodium ion is present in sodium oxide, while magnesium ion is present in magnesium oxide.
Why do ionic compounds have high melting points?
Answer: The force of attraction in ionic bonds is very strong and it is difficult to overcome that force. Hence, ionic compounds have high melting points.
Define the following terms.
Answer: A substance which naturally occurs in the earth’s crust and has a uniform composition is called mineral.
Answer: A mineral from which a substance can be profitably extracted is called an ore.
Answer: The impurities present in an ore are called gangue.
Name two metals which are found in nature in the free-state.
Answer: Silver and gold
What chemical process is used for obtaining a metal from its oxide?
Answer: For obtaining a metal from its oxide, we need to use reduction. This process is carried out by heating the metal oxides; usually with a reducing agent.
Metallic oxides of zinc, magnesium and copper were heated one by one with zinc, magnesium and copper. In which cases will you find displacement reactions taking place?
Answer: Displacement reaction takes place only when zinc oxide is headed with magnesium. And No reaction takes place in other cases.
Which metals do not corrode easily?
Answer: Metals which are at the bottom of reactivity series do not corrode easily, e.g. copper, silver and gold.
What are alloys?
Answer: A homogenous mixture of two or more than two metals or a metal and a non-metal is called an alloy.