Class 10 Metals and Non-metals Short Answer
Questions Based On Topic-1
Metals: Physical properties of metals, chemical properties of metals & non-metal oxide.
VERY SHORT ANSWER TYPE QUESTIONS [1 Mark]
Q.1. Give examples of two elements that are metallic.
Ans. Iron (Fe) and Gold (Au).
Q.2. Name any one metal which reacts neither with cold water nor with hot water but reacts with steam to produce hydrogen gas. [CBSE 2006, HOTS]
Ans. Iron (Fe).
[3Fe (s) + 4H2O(g) →Fe3O4(s)+4H2 (g)]
Q.3. Name two metals which are highly malleable and ductile?
Ans. Gold (Au) and Silver(Ag).
Q. 4. Write a chemical equation to represent the reaction taking place between sodium metal and cold water. [CBSE 2005]
Ans. 2Na(s) + 2H2O(l)→ 2NaOH(aq) + H2(g).
Sodium Water Sodium Hydroxide Hydrogen.
Q.5. Name two metals which react with very diluted nitric acid to produce hydrogen gas. [CBSE 2011]
Ans. Manganese (Mn) and magnesium (Mg).
Q. 6. What is seen to happen when a piece of sodium metal is dropped into water? (CBSE 2005]
Ans. It is a violent reaction. Thus, sodium metal catches fire.
2Na(s) + 2H2O(l)—→ 2NaOH(aq) + H2(g)
Q.7. Give any two important characteristics of metals.
Ans. Metals are:
(i) Malleable and ductile and
(ii) Good conductor of heat and electricity.
Q.8. From amongst the metal sodium, calcium, aluminium, copper and magnesium, name the metal. Which reacts with water only on boiling and (ii) another which does not react even with steam [CBSE 2008]
Ans. (i) Magnesium (Mg)
(ii) Copper (Cu)
Q.9. Why is H2 gas not evolved when metal is treated with Nitric acid (HNO3)? [HOTS]
Ans. Nitric acid (HNO3) is a strong oxidising agent and it oxidises the hydrogen (H) gas liberated into water (H2O) and itself get reduced to some oxide of nitrogen like nitrous oxide (N2O), nitric oxide (NO) and nitrogen dioxide (NO2).
Q. 10. Give an example of a metal which is a liquid at room temperature. (CBSE 2011]
Ans. Mercury (Hg).
Q. 11. Name the metals that are soft and can be cut with a knife.
Ans. Sodium (Na) and Potassium (K).
Q. 12. Name the metal which has a very low melting point and can melt with the heat of your palm. [CBSE 2012]
Ans. Gallium (Ga) and Caesium (Cs).
Q. 13. Name the metal which is the poorest conductor of heat and which one is the best conductor of heat.
Ans. The poorest conductor of heat: Lead (Pb) and The best conductor of heat: Silver (Ag).
Q. 14. What are the two metals other than silver (Ag) and gold (Au) which are not attacked even by steam?
Ans. Lead (Pb) and copper (Cu).
Q. 15. Identify the most reactive and the least reactive metal amongst the following: AI, K, Cu, Au
Ans. Most reactive metal: K (Potassium)
Least reactive metal: Au (Gold).
Q. 16. In sodium (Na) and Aluminium (Al), which one is more metallic?
Ans. Sodium (Na) is more metallic.
Q. 17. Name two amphoteric oxides.
Ans. Aluminium oxide (Al2O3) and Zinc oxide (ZnO).
Q. 18. Name a metal which exists in a liquid state at room temperature. [CBSE 2012]
Ans. Mercury (Hg).
Q. 19. Which one of the following elements forms a basic oxide?
S, P, Si, Ca
Ans. Calcium (Ca) metal forms basic oxide (CaO).
Q. 20. Identify the most reactive and least reactive metals from the reaction below:
CuSO4 + Fe → FeSO4 + Cu
FeSO4 + Zn → ZnSO4 + Fe [HOTS]
Ans. Zinc (Zn) is most reactive because it displaces Fe from FeSO4 and Cu is least reactive because it was displaced by Fe.
Q. 21. What are the three metals present below copper in the reactivity (activity) series of metals?
Ans. Mercury (Hg), Silver (Ag) and Gold (Au).
Q. 22. Why are the metals electropositive?
Ans. Metals are electropositive in nature because they have a tendency to lose electrons to form positive ions.
Q.23. Why do we use copper and aluminium wire for transmission of electric currents? [CBSE 2011]
Ans. Aluminium (Al) and copper (Cu) metals are a good conductor of electricity and have low resistivity.
Q. 24. Arrange the following metals in order of their decreasing activity:
Fe, Zn, Cu, Ca, Ag, Mg, Al.
Ans. Ca > Mg > Al> Zn > Fe>Cu > Ag.
SHORT ANSWER TYPE QUESTIONS [2 marks]
Q.1. Which gas is produced when a metal reacts with diluted hydrochloric acid? Write the chemical reaction when iron reacts with dilute H2 SO4 Ans. Hydrogen gas (H)2 is produced when a metal reacts with diluted hydrochloric acid. Iron and dilute H2SO4 reacts as follows:
Fe(s) +H2SO4(dil) → FeSO4(aq) +H2(g)
Hydrogen gas is evolved in this reaction also.
Q.2. Nikita took Zn, Al, Cu, Fe, Mg, Na metals and put each metal in cold water and then hot water. She reacted to the metal with steam
(i) Name the metal which reacts with cold water.
(ii) Which of the above metals react with steam?
(iii) Name the metal which reacts with hot water.
(iv) Arrange these metals in order of increasing reactivity [HOTS]
Ans. (i) Na (Sodium)
(ii) Al, Zn, Fe
(iii) Mg (Magnesium)
(iv) Na > Mg > Al > Zn> Fe > Cu
Q.3. Why does copper not liberate hydrogen when reacting with diluted sulphuric acid? Ans. Copper is placed below hydrogen in the activity series. It cannot lose electrons to H+ ions of acid. Therefore, hydrogen gas is not evolved when the copper reacts with diluted sulphuric acid.
Cu(s) + H2SO4(aq) → No reaction
Q.4. What would you observe when zinc is added to a solution of Iron (II) sulphate?
Ans. The green colour of the solution will slowly disappear. Zinc will dissolve and iron will get precipitated at the bottom of the breaker.
Zn(s)+FeSO4 (aq)- > ZnSO4(aq)+Fe(s)
Q.5. Both calcium and magnesium are heavier than water but still float over it. Explain (CBSE 2012]
Ans. The densities of Calcium and Magnesium are 1.74g/cc and 1.55g/cc respectively while The water is 1.0g/cc at room temperature. However, both of them float over the water surface. Actually hydrogen gas is evolved when these metals react with water. It is in the form of bubbles which stick to the metal surface. Therefore, they float over the water.
Ca + 2H2O → Ca(OH)2 + H2
Q.6. A student was given Mg, Zn, Fe, and Cu metals. He put each of them in dil HCl contained in different test tubes. Identify which of them: [HOTS]
(i) will not displace H, from dil HCI
(ii) forms a pale green substance
(iii) will give the H2 with 5% HNO3
(iv) will be displaced from its salt solution by all other metals.
Ans. (i) Cu (ii) Fe (iii) Cu (iv) Cu
Q.7. Give a reason why Platinum (Pt), Gold (Au) and silver (Ag) are used to make jewellery.
Ans. Platinum, gold and silver are placed at the bottom of the activity series and are very little reactive in nature and are known as noble metals. They are not even affected by air, water or even by chemicals. Since they have bright lustre, we can use them for making jewellery.
Q.8. A student set up an electric circuit as shown in Fig. He placed the metal to be tested on the circuit between terminals A and B as shown.
(1) Does the bulb glow? What does this indicate?
(ii) Why are electric wires coated with rubber-like materials? [HOTS]
Ans. (i) Yes, the bulb glows, this indicates that metal is a good conductor of electricity.
(ii) The rubber-like substance is a bad conductor of electricity.
Q.9. Why are metals generally lustrous?
Ans. Metals are generally lustrous because they have a shiny surface and when light falls on the surface of metal electrons absorb photons of light and releases energy as light.
Q. 10. Name two metals which can displace hydrogen from dilute acid and two metals which cannot do so?
Ans. Sodium and calcium can displace hydrogen from diluted acids.
Copper and silver cannot displace hydrogen from diluted acid.
Q. 11. Choose the metal which can displace zinc from zinc sulphate solution: Lead, Copper, Magnesium, Silver [CBSE 2005]
Ans. Magnesium (Mg)
Mg(s) + ZnSO4(aq)-> MgSO4 (aq) + Zn(s)
12. What are amphoteric oxides? Give examples. (CBSE 2012]
Ans. Amphoteric oxides are oxides which can act both as eg → Aluminium oxide (Al2O3) and Zinc oxide (ZnO)
Al202 + 6HCl → 2AlCI3 + 3H,0
Al2O3 + 2NaOH → 2NaAlO2 +H2O
Q. 13. Why is sodium kept immersed in Kerosine oil ? [CBSE 2011] Ans. Sodium reacts both with air and water. It is therefore kept in kerosene oil in order to avoid contact with both air and water.
2Na(s) + H2O(l) → Na2O(s) +H2(g).
Q. 14. Metals are kept in the reactivity series. Why hydrogen is kept in the series even though it is not a metal?
Ans. Hydrogen is a non-metal but still, it is placed in the reactivity series because it behaves as an electropositive element like metals i.e., which can lose electrons to form positive ions.
H → H+ + e–
Q. 15. Give two examples each of the metals that are good conductors and poor conductors of heat respectively. [NCERT Exemplar]
Ans. Best conductors: Copper, silver.
Poor Conductor: Gallium, mercury.
Q.16. Name one metal and one non-metal that exists in a liquid state at room temperature. Also, name the two metals that have a melting point of less than 310 K (37°C). [NCERT Exemplar]
Ans. Metal – Mercury (Hg); Non-metal: Bromine (Br) exists in a liquid state at room temperature. Gallium (Ga) and Caesium (Cs) are metals with melting points less than 310 K.
Q. 17. Metal M does not liberate hydrogen from acid but reacts with oxygen to give it a black coloured product. Identify M and black coloured products and also explain the reaction of M with oxygen.
Ans. M is copper (Cu) and the black coloured product is copper (II) oxide (CuO).
2Cu + O2 —–> 2CuO