Below are some important questions for class 10 science chapter 3 – Metals and Non-metals that students must study thoroughly.There are two main categories of elements: metals and non-metals. Metals are highly reflective, highly ductile, and excellent conductors of heat and electricity. A non-metal is a chemical element that lacks the properties of a metal and gains electrons when it reacts with metals and forms an acid when combined with oxygen and hydrogen. The reactivity of different metals with water and dilute acids varies. An activity series is a list of common metals arranged in increasing order of reactivity.
Some important questions topics for class 10 science chapter 3 – Metals and Non-metals are:
- The physical properties of metals and non-metals
- In the presence of water, what happens when metals react?
- Series on Reactivity
- What is the reaction between metals and non-metals?
- Metal extraction is a low activity in the activity series.
Below are some of the important questions for class 10 science chapter 3 – Metals and Non-metals from an examination point of view.
Class 10 Science Important Questions Chapter 3 – Metals and Non-metals
Q1. Why should the metal sulphides and carbonates be converted to metal oxides in the extraction process of metal?
It is easier to obtain metals from their oxides than carbonates or sulphides. So, the ore is first converted into an oxide. A carbonate ore is first converted into oxide ore by calcination. Sulphide ore is converted into oxide ore by roasting.
Q2. Compound X and aluminium are used to join railway tracks.
(a ) Identify the compound X.
(b ) Name the reaction.
(c ) Write down its reaction.
(a ) Compound X Is ferrous oxide (Fe2O3).
(b ) This reaction is called a thermite reaction.
(c ) 2 Al + Fe2O3 → 2 Fe + Al2O3 + heat
Q3. The following reaction takes place when the aluminium powder is heated with MnO2
3 MnO2 (s) + 4 Al (s) → 3 Mn (I) + 2 Al2O3 (l) + Heat
(a ) Is aluminium getting reduced?
(b ) Is MnO2 getting oxidised?
(a ) No, aluminium is not getting reduced.
(b ) No, MnO2 is not getting oxidised.
In this reaction, aluminium gets oxidised as oxygen gets combined with it. Since oxygen is removed from MnO2, it is getting reduced.
Q4. A metal A, which is used in the thermite process, when heated with oxygen, gives an oxide B, which is amphoteric in nature. Identify A and B. Write down the reactions of oxide B with HI and NaOH.
Metal A is aluminium, and B is aluminium oxide (Al2O3).
The reaction of aluminium oxide with HCl
Al2O3 + 6 HCl → 2 AlCl3 + 3 H2O
The reaction of aluminium oxide with NaOH:
Al2O3 + 2 NaOH → 2 NaAlO2 + H2O
Q5. What happens when
(a) ZnCO3 is heated without oxygen?
(b) A mixture of Cu2O and Cu2S is heated?
(a) When zinc carbonate is heated without oxygen, we get zinc oxide and carbon dioxide.
ZnCO3 → ZnO + CO2
(b) When a mixture of copper oxide and copper sulphide is heated. We get the pure copper.
2 Cu2O + Cu2S → 6 Cu + SO2
Q6. An element A reacts with water to form a compound B used in whitewashing. The compound B on heating forms an oxide C which gives back B on treatment with water. Identify A, B and C and give the reactions involved.
- A is calcium. It reacts with water to give calcium hydroxide.
- B is calcium hydroxide. It is used for whitewashing.
- C is calcium oxide.
The reactions are as follows:
Ca + 2 H2O → Ca(OH)2 + H2
Ca(OH)2 → CaO + H2O
CaO + H2O → Ca(OH)2
Q7. Give the reaction involved during extraction of zinc from its ore by
(a ) Roasting of zinc ore
(b ) Calcination of zinc ore
(a ) 2 ZnS + 3 O2 → 2 ZnO + 2 SO2
(b ) ZnCO3 → ZnO + CO2
Q8. By what processes do you concentrate the following ores:
- Al2O3.2H2O (bauxite).
- PbS (galena) is concentrated by the froth floatation method.
- Fe2O3 (haematite) is concentrated by magnetic separation.
- Al2O3.2H2O (bauxite) is concentrated by a leaching process (chemical method).
Q9. What property of hydrogen is observed in the following experiments?
- Balloon, filled with hydrogen, floats.
- Pop sound is heard when a burning splint is introduced at the mouth of a hydrogen filled jar.
- When black cupric oxide is heated in a stream of hydrogen, reddish colour is obtained.
- Hydrogen is light. So hydrogen filled balloons float.
- Pop sound is due to the combustible property of hydrogen. Hydrogen burns with oxygen at the mouth of the hydrogen filled jar.
- Hydrogen has a reduced property. Hence it reduces black cupric oxide to red copper metal.
Q10. Give reasons for the following
- Silicon counts among metalloids
- Carbon is not used for making aluminium from aluminium oxide.
- For making hydrogen by reaction with hydrochloric acid, granulated zinc is preferred to a block of zinc.
- Silicon shows properties of both metals and non-metals and hence silicon counts among metalloids.
- Carbon has less affinity for oxygen than Aluminium and hence it cannot eliminate oxygen from Aluminium oxide.
- Zinc granules are preferred to a block of zinc because it offers a large surface area for the reaction with the acid.