Advertisements
Advertisements
प्रश्न
Give a reason why iron objects rust easily but the iron pillar at Qutab Minar has not rusted over the years.
उत्तर
The iron pillar at Qutab Minar has not rusted for 1600 years because of the following reasons:
- The high purity and great mass of iron may have created a temperature stabilizer thus reducing the condensation of moisture on it.
- The protective scale or passive iron coating formation on the surface, better forge welding and absence of impurities in iron – also may have dissuaded corrosion.
APPEARS IN
संबंधित प्रश्न
Mark ‘T’ if the statement is true and ‘F’ if it is false.
Sodium is a very reactive metal. ( )
Name two alloys of iron. What elements are present in these alloys?
Name one ore of manganese. Which compound of manganese is present in this ore? Also write its chemical formula.
Mention two uses of the following metals and non-metals
Gold
Fill in the blank
A metal that gives dazzling effect to crackers when they explode is ______
Write ‘true’ or ‘false’ for the following statement.
Iodine acts as an antiseptic in the form of a tincture of iodine.
Aluminium is not used to make :
Write ‘True’ or ‘False’ in front of following statement.
Magnesium is used in making light weight alloys of aluminium.
State two important uses of following metal
Uses of tin
Write name.
Molecular formula of the common ore of aluminium.
Write scientific reason.
Sodium is always kept in kerosene.
Write scientific reason.
Anodes need to be replaced from time to time during the electrolysis of alumina.
When a copper coin is dipped in silver nitrate solution, a glitter appears on the coin after some time. Why does this happen? Write the chemical equation.
Which is the non-ionic compound in the compounds given below.
AgNO3 + Nacl → AgCl + NaNO3
With reference to the following metals state their use in daily life metal:
Silver
Name the following:
A halogen which is a solid at room temperature.
Aluminium: _______: gold : : electric insulator
Silver and copper are very good conductors of electricity.
Match the following
| i. | Silica | a. | Caustic potash |
| ii. | Potassium hydroxide | b. | Sand |
| iii. | Sodium hydroxide | c. | Calamine |
| iv. | Zinc carbonate | d. | Caustic soda |
