ncert solution metal and non metal for class 10

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.

(i) Metal that exists in liquid state at room temperature → Mercury

(ii) Metal that can be easily cut with a knife → Sodium

(iii) Metal that is the best conductor of heat → Silver

(iv) Metals that are poor conductors of heat → Mercury and lead

Question 2:

Explain the meanings of malleable and ductile.

Malleable: Substances that can be beaten into thin sheets are called malleable. For example, most of the metals are malleable.

Ductile: Substances that can be drawn into thin wires are called ductile. For example, most of the metals are ductile.

Question 1:

Why is sodium kept immersed in kerosene oil?

Sodium and potassium are very reactive metals and and combine explosively with air as well as water. Hence, they catch fire if kept in open. Therefore, to prevent accidental fires and accidents, sodium is stored immersed in kerosene oil.

Question 2:

Write equations for the reactions of

(i) iron with steam

(ii) calcium and potassium with water

Question 3: Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows. Metal Iron (II) sulphate Cooper (II) sulphate Zinc sulphate Silver nitrate A. No reaction Displacement B. Displacement No reaction C. No reaction No reaction No reaction Displacement D. No reaction No reaction No reaction No reaction Use the Table above to answer the following questions about metals A, B, C and D. (i) Which is the most reactive metal? (ii) What would you observe if B is added to a solution of copper (II) sulphate? (iii) Arrange the metals A, B, C and D in the order of decreasing reactivity. Explanation A + FeSO4 → No reaction, i.e., A is less reactive than iron A + CuSO4 → Displacement, i.e., A is more reactive than copper B + FeSO4 → Displacement, i.e., B is more reactive than iron B + ZnSO4 → No reaction, i.e., B is less reactive than zinc C + FeSO4 → No reaction, i.e., C is less reactive than iron C + CuSO4 → No reaction, i.e., C is less reactive than copper C + ZnSO4 → No reaction, i.e., C is less reactive than zinc C + AgNO3 → Displacement, i.e., C is more reactive than silver D + FeSO4/CuSO4/ZnSO4/AgNO3 → No reaction, i.e., D is less reactive than iron, copper, zinc, and silver From the above equations, we obtain: (i) B is the most reactive metal. (ii) If B is added to a solution of copper (II) sulphate, then it would displace copper. B + CuSO4 → Displacement (iii) The arrangement of the metals in the order of decreasing reactivity is: B > A > C > D

Question 4:

Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.

Hydrogen gas is evolved when dilute hydrochloric acid is added to a reactive metal.

When iron reacts with dilute H2SO4, iron (II) sulphate with the evolution of hydrogen gas is formed.

Question 5:

What would you observe when zinc is added to a solution of iron (II) sulphate? Write the chemical reaction that takes place.

Zinc is more reactive than iron. Therefore, if zinc is added to a solution of iron (II) sulphate, then it would displace iron from the solution.

Question 1:

(i) Write the electron-dot structures for sodium, oxygen and magnesium.

(ii) Show the formation of Na2O and MgO by the transfer of electrons.

(iii) What are the ions present in these compounds?

(i) The representation of elements with valence electrons as dots around the elements is referred to as electron-dot structure for elements.

(ii)

(iii) The ions present in Na2O are Na+ and O2− ions and in MgO are Mg2+ and O2− ions.

Question 2: