A brown substance x on heating in air forms a substance y when hydrogen gas is passed over heated y it again changes back into x
A) name the substance x and y.
B) name the type of chemical reaction occurring both the changes.
C) write the chemical equation of the reaction.
Answers
Answer:
(I) Substance X is 'Copper'
Y is 'Copper oxide
(II)Oxidation and reduction.
(iii) The chemical equations involved are:-
2Cu (s) + O2 (g) ----> 2CuO
CuO + H2 (g) ----> Cu + H2O
Explanation:
Answer:
Question 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.
Answer:
(i) Mercury
(ii) Sodium
(iii) Silver
(iv) Lead
Question 2
Explain the meanings of malleable and ductile.
Answer:
Malleable : A metal that can be beaten into thin sheets on hammering is called malleable.
Ductile : A metal which can be drawn into thin wires is called ductile.
Malleable Meaning in Hindi
pg46
Question 2
Name two metals which are found in nature in the free state.
Answer:
Gold and platinum
Question 3
What chemical process is used for obtaining a metal from its oxide.
Answer:
Reduction process is used for obtaining a metal from its oxide.
For example, zinc oxide is reduced to metallic zinc by heating with carbon.
ZnO(s) + C(s) → Zn(s) + CO(g)
Besides carbon, highly reactive metals like sodium, calcium, aluminium etc. are used as reducing agents. These displace metals of low reactivity from their oxides.
For example,
Fe2O3(s) + 2Al(s) → 2Fe(l) + Al2O3(s) + Heat
Gold is Metal or Nonmetal ?Gold is a metal found in nature in the free state
Class 10 Metals and Non Metals NCERT Book Page Number: 55
Question 1
Metallic oxides of zinc, magnesium and copper were heated with the following metals :
Metal Zinc Magnesium Copper
1. Zinc oxide
2. Magnesium oxide
3. Copper oxide
In which cases will you find displacement reactions taking place ?
Answer:
A more reactive metal can displace a less reactive metal from its oxide. But out of zinc, magnesium, and copper metals, magnesium is the most reactive, zinc is less reactive whereas copper is the least reactive metal.
The displacement will take place in the following cases :
Metal Zinc Magnesium Copper
1. Zinc oxide – Displacement –
2. Magnesium oxide – – –
3. Copper oxide Displacement Displacement –
Question 2
Which metals do not corrode easily ?
Answer:
Gold and Platinum.
Question 3
What are alloys ?
Answer:
An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. For example, bronze is an alloy of copper and tin.
NCERT Solutions for Class 10 Science Chapter 3 Textbook Chapter End Questions
Metals and Nonmetals Class 10 Question 1.
Which of the following pairs will give displacement reactions ?
(a) NaCl solution and copper metal.
(b) MgCl2 solution and aluminium metal.
(c) FeSO4 solution and silver metal.
(d) AgNO3 solution and copper metal.
Answer:
(d) AgNO3 solution and copper metal.
Question 2.
Which of the following methods is suitable for preventing an iron frying pan from rusting ?
(a) Applying grease
(b) Applying paint.
(c) Applying a coating of zinc
(d) All the above.
Answer:
(