Thursday, 17 December 2020

CBSE Class 10 - Chemistry - METALS AND NON-METALS (Very Short Answer Based Questions) #class10Chemistry #Metals #NonMetals #eduvictors #cbse2020

CBSE Class 10 - Chemistry - METALS AND NON-METALS (Very Short Answer Based Questions) 

CBSE Class 10 - Chemistry - METALS AND NON-METALS (Very Short Answer Based Questions) #class10Chemistry #Metals #NonMetals #eduvictors #cbse2020

Q1. A green layer is gradually formed on a copper plate left exposed to air for a week in a  bathroom. What could this green substance be? 

Answer. It is due to the formation of basic copper carbonate [CuCO₃.Cu(OH)₂].


Q2. Why are elements of Group IA i.e. H, Li, Na, K, Cs and Fr called alkali metals?

Answer. Because oxides of these elements dissolve in water to give alkali or soluble hydroxides.  


Q3. A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance,   whereas Z is a good conductor of electricity. Identify X, Y and Z. 

Answer. ‘X’ is carbon, ‘Y’ is diamond as it is the hardest natural substance and ‘Z’ is graphite as   it is good conductor of electricity. 

Q4. Between Calcium (Ca) and Barium (Ba) metals, which form monoxide?

Answer. Calcium (Ca) combines with oxygen to form Calcium oxide (CaO) - a monoxide.

2Ca + O₂  ------> 2CaO


Q5. Metals generally occur in solid state. Name and write symbol of a metal that exists in liquid  state at room temperature. 

Answer. Mercury(Hg) exists in liquid state at room temperature. 


Q6. Which of the following two metals will melt at body temperature (37 °C) ? 

Gallium, Magnesium, Caesium, Aluminium 

Answer. Gallium and Caesium 


Q7. Are carbonates of Li and Na soluble in water?

Answer. No. These carbonates are insoluble.


Q8. From amongst the metals sodium, calcium, aluminium, copper and magnesium, name the  metal 

(a) which reacts with water only on boiling, and 

(b) another which does not react even with steam. 

Answer

(a) Magnesium reacts with water only on boiling. 

(b) Copper does not react even with steam. 


Q9. Which one of the following metals does not react with oxygen even at high temperatures ? 

(a) Calcium (b) Gold (c) Sodium 

Answer. (b) Gold does not react with oxygen even at high temperatures. 


Q10. The reaction between Fe₂O₃ and Al is popularly known as _________. (fill in the blank).

Answer: Thermit reaction.


Q11. Name any one metal which reacts neither with cold water nor with hot water, but reacts   with heated steam to produce hydrogen gas. 

Answer. Iron; 3Fe(s) + 4H₂O(g) → Fe₃O₄(s) + 4H₂(g) 


Q11. Why does calcium float in water? 

Answer. It is because hydrogen gas is formed which sticks to surface of calcium, therefore it  floats.  


Q12. Name a non-metal which is lustrous and a metal which is non-lustrous.  

Answer. Iodine is a non-metal which is lustrous, lead is a non-lustrous metal. 


Q13. Which gas is liberated when a metal reacts with an acid? How will you test the presence of   this gas? 

Answer. Hydrogen gas is formed. Bring a burning matchstick near to it, H₂ will burn explosively   with ‘pop’ sound. 


Q14. Name the metal which reacts with a very dilute HNO₃ to evolve hydrogen gas. 

Answer. Magnesium 


Q15. Name two metals which are found in nature in the free state. 

Answer.(i) Gold (ii) Silver 


Q16. What is the valency of silicon with atomic number 14? 

Answer. Its valency is equal to 4. 


Q17. What is the valency of phosphorus with atomic number 15? 

Answer. Phosphorus has valency 3. 


Q18. What is the valency of an element with atomic number 35? 

Answer. Its valency is 1. 


Q19. Arrange the following metals in the decreasing order of reactivity: Na, K, Cu, Ag. 

Answer. K > Na > Cu > Ag 


Q20. An element forms an oxide, A₂O₃ which is acidic in nature. Identify A as a metal or non- metal. 

Answer. ‘A’ is non-metal as non-metallic oxides are acidic in nature.


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