Science – Metals and Non Metals
Very Short Answer Type Questions
Q.1) 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.
Ans) (i) Mercury, (ii) Sodium, (iii) Silver and copper, (iv) Lead.
Q.2) Name two metals which are found in nature in the free state?
Ans) Gold, silver and platinum. These metals are at the bottom of the reactivity series.
Q.3) Which chemical process is used for obtaining a metal from its oxide?
Ans) A metal can be extracted from its oxide by the process of reduction.
2HgO(s) → Heat → 2Hg (l) + O2(g)
Q.4) Which metals do not corrode easily?
Ans) Metals which have low reactivity such as silver, gold do not corrode easily.
Q.5) Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Ans) Iron and aluminium will displace hydrogen from dilute acids as they are more reactive than hydrogen. Mercury and copper cannot displace hydrogen from dilute acids as they are less reactive than hydrogen.
Q.6) Write equations for the reactions of:
(i). Iron with steam.
(ii). Calcium potassium with water.
(iii). potassium with water.
Ans) (i). 3Fe(s)+ 4 H2O(g) → Fe3O4(aq) + 4H2(g)
Ans) (ii). Ca(s) + 2H2O(l) → Ca(OH)2(aq) + H2(g) + Heat
Ans) (iii). 2K(s) + 2H₂O(l) → 2KOH(aq) + H₂(g) + Heat
Q.7) What are amphoteric oxides? Give two examples of amphoteric oxides.
Ans) Those oxides that behave as both acidic and basic oxides are called amphoteric oxides. Examples: aluminum oxide (Al₂O₃), zinc oxide (ZnO).
Q.8) In the electrolytic refining of a metal M, What would you take as the anode, the cathode and the electrolyte?
Ans) . In the electrolytic refining of a metal M:
- Anode – Impure metal M.
- Cathode – Thin strip of pure metal M.
- Electrolyte – Salt solution of metal M.
Q.9) What type of oxides are formed when non-metals combine with oxygen?
Ans) When non-metals combine with oxygen, then neutral or acidic oxides are formed. Examples of acidic oxides are NO2, SO2 and examples of neutral oxides are NO and CO.
Q.10) Define corrosion.
Ans) Corrosion “Some metals get reacted with atmospheric oxygen in presence of moisture forming their oxides or hydroxides, and are decayed slowly. This is called corrosion.”
Q.11) Write two ways of prevention of corrosion.
Ans) See Long Answer Type Q. No. 2.
Q.12) Explain meaning of malleability and ductility.
Ans) Malleability – “The property of metals by virtue of which they convert in sheets on hammering is called malleability.”
Ductility – The property of metals by virtue of which they can be drawn into wires is called ductility.”
Q.13) Name two metals which are found in nature in free state.
Ans) (i) Gold (Au), (ii) Silver (Ag).
Q.14) Define calcination.
Ans) The carbonate ores are changed into oxide by heating strongly in limited air. This process is known as calcination.
Q.15) Define Roasting.
Ans) The sulphide ores are converted into oxides by heating strongly in the presence of excess air this process is known as roasting.