Metals and Non-Metals: Class 10 Science Q&A · Page 6
114 free answers on Metals and Non-Metals (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10CBSE
What are alloys?
Solution: An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal.
- ScienceClass 10CBSE
Which metals do not corrode easily?
Solution: Gold and platinum are the metals which do not corrode easily
- ScienceClass 10CBSE
Metallic oxides of zinc, magnesium and copper were heated with the following metals. Metal Zinc Magnesium Copper Zinc Oxide Magnesium Oxide Copper Oxide
A more reactive metal can displace a less reactive metal from its oxide. Among Zinc, Magnesium, and Copper metals, magnesium is the most reactive, copper is the least reactive metal and zinc is less reactive .The displacement reaction will take place in the following cases Metal Zinc Magnesium Copper</stron
- ScienceClass 10CBSE
What chemical process is used for obtaining a metal from its oxide?
Reduction method is used to obtain metal from its oxide. Ex: Zinc oxide is reduced to metallic zinc by heating with carbon. ZnO + C → Zn + CO Ex: Lead oxide is reduced to lead by heating with carbon PbO +C → Pb + CO
- ScienceClass 10CBSE
Name two metals which are found in nature in the free state
Gold and platinum are the two metals found in free state in nature.
- ScienceClass 10CBSE
Define the following terms. (i) Mineral (ii) Ore (iii) Gangue
Minerals are compounds (also known as elements) which are found naturally in the earth’s crust. E.g. Alums, K2SO4.Al2(SO4)3.24H2O, etc. Ores are minerals from which metal can be extracted Ex: Bauxite Al2O3.2H2O is the ore of Al, copper pyrite CuFeS2. All minerals are not considered as ores but all ores are also minerals. <
- ScienceClass 10CBSE
(i) Write the electron-dot structures for sodium and oxygen. (ii) Show the formation of Na2O and MgO by the transfer of electrons. (iii) What are the ions present in these compounds?
Solution: (i) Sodium: Oxygen: (ii) Formation of Magnesium oxide: When magnesium reacts with oxygen, the magnesium atom transfers its two outermost electrons to an oxygen atom. By losing two electrons, the magnesium atoms form a magnesium ion (Mg2+), and by gaining two electrons, the oxygen atom forms an oxide ion (O2-). Mg: + → MgO
- ScienceClass 10CBSE
What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical reaction that takes place.
Zinc is more reactive (more electro positive) than iron. Therefore, Zinc displaces Iron from its salt solution. The colour of ferrous sulphate is pale green, which turns colourless. FeSO4 + Zn → ZnSO4 + Fe(s) Light green Zinc sulphate(Colourless)
- ScienceClass 10CBSE
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
Hydrogen gas is liberated when dilute HCl is added to a reactive metal. Fe(s) + H2SO4(aq) → FeSO4(aq) + H2(g)
- ScienceClass 10CBSE
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows Metal Iron(II) sulphate Copper(II) sulphate Zinc sulphate Silver Nitrate A No reaction Displacement – – B Displacement – – – C No reaction No reaction No reaction Displacement D No reaction No reaction No reaction No reaction Use the table above to answer the following questions about metals A, B, C and D. 1. Which is the most reactive metal? 2. What would you observe if B is added to a solution of Copper (II) sulphate? 3. Arrange the metals A, B, C and D in the order of decreasing reactivity.
(i) Metal B is the most reactive as it gives displacement reaction with iron (II) sulphate. (ii) When metal B is added to copper (II) sulphate solution, a displacement reaction will take place because of which the blue colour of copper (II) sulphate solution will fade and a red-brown deposit of copper will be formed on metal B. (iii)Metal B is the most reactive because it displaces iron from its salt solution. Metal A is less reactive
- ScienceClass 10CBSE
Write equations for the reactions of (i) iron with steam (ii) calcium and potassium with water
(i) Iron reacts with steam to form a magnetic oxide of Fe with the liberation of H2. 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g) (ii) Calcium reacts with water to form calcium hydroxide and hydrogen. Ca(s) + 2H2O(I) → Ca(OH)2(aq) + H2(g) Potassium reacts with cold water violently immedia
- ScienceClass 10CBSE
Why is sodium kept immersed in kerosene oil?
Sodium is a reactive metal. If kept open it will react with oxygen to explore and catch fire. Sodium metal is kept immersed in kerosene to prevent their reaction with oxygen, moisture and carbon dioxide of air.
- ScienceClass 10CBSE
Explain the meanings of malleable and ductile.
Solution: Metals which can be beaten to sheets are said to be malleable Metals which can be drawn into thin wires are said to be ductile
- ScienceClass 10CBSE
Give an example of a metal which (i) Is a liquid at room temperature? (ii) Can be easily cut with a knife? (iii) Is the best conductor of heat? (iv) Is a poor conductor of heat?
(i) Mercury is the metal which is liquid at room temperature (ii) Sodium and potassium are the metals which can be cut with a knife (iii) Silver is the best conductor of heat (iv) Mercury and lead are poor conductor of heat.