Give reason for the following:
Carbonate and sulphide ores are usually converted into oxides during the process of extraction of metals.
Answer
Carbonate and sulphide ores are usually converted into oxides because it is easier to obtain metals from their oxides (by reduction) than from carbonates or sulphides.
If A, B, C, D, E, F, G, H, I, J and K represent metals in the decreasing order of their reactivity, which one of them is most likely to occur in a free state in nature?
Answer
K being the lowest in the reactivity series is least reactive and is most likely to occur in a free state in nature.
Arrange the following metals in order of their chemical reactivity, placing the most reactive metal first:
Magnesium, Copper, Iron, Sodium, Zinc, Lead, Calcium.
Answer
Sodium > Calcium > Magnesium > Zinc > Iron > Lead > Copper
What will happen if a strip of copper is kept immersed in a solution of silver nitrate $\left( A _{ g } NO _3\right)$ ?
Answer
When a strip of copper metal is immersed in silver nitrate solution, the solution gradually becomes blue and a shining greyish-white deposit of silver metal is formed on copper strip.
How would you show that silver is chemically less reactive than copper?
Answer
If a strip of silver metal is kept immersed in copper sulphate solution for some time, then no reaction occurs. This shows that silver is not able to displace copper from copper sulphate solution.
Describe the reaction of potassium with water. Write the equation of the reaction involved.
Answer
Potassium reacts violently with cold water to form potassium hydroxide and hydrogen gas.
$2\text{K(s)}+2\text{H}_2\text{O(l)}\rightarrow2\text{KOH(aq)}+\text{H}_2\text{(g)}+\text{Heat}$
Sodium is a very reactive metal so it reacts vigorously with the oxygen of air and catches fire. It is kept immersed in kerosene oil to protect it from the action of oxygen, moisture and carbon dioxide of air and to prevent accidental fires.
What type of chemical bonds are present in a solid compound which has a high melting point, does not conduct electricity in the solid state but becomes a good conductor in the molten state?