Answer: Option A. -> mercury
:
A

An ore consists of desired metal compound from which the metal can be extracted profitably.
Cinnabar is an ore of mercury. Its chemical formula is $\text{HgS}$.
It is the most common source used for refining elemental mercury.

Answer: Option D. -> Lithium 
:
D

Metals are usually very hard but alkali metals (lithium, sodium, potassium) are so soft that they can be cut with a knife. This is because they have very low densities. 

Answer: Option C. -> coating zinc
:
C
Galvanisation is the method of applying a protective layer on metal to prevent the metal from corrosion. 
A coating of zinc is applied on iron or steel during galvanization. It prevents iron from coming in direct contact with air and water. Thus, preventing it from rusting.

Answer: Option C. -> Metals above hydrogen in the reactivity series cannot displace hydrogen from dilute acids.
:
C

• Alloys that contain mercury are known as amalgams.


• The metals high up in the reactivity series are very reactive.


• More reactive metals can replace less reactive metals.


• Metals which are above hydrogen in the reactivity series will displace hydrogen from dilute acids.

For example: $\text{Fe}\text{(s)}+{\text{CuSO}}_4\text{(aq)}\to {\text{FeSO}}_4\text{(aq)}+\text{Cu}\text{(s)}$
Here, iron is more reactive than copper. So, it displaces copper from its solution.

Answer: Option B. -> Low Melting Point
:
B

Metals exhibit the following physical properties-
- They are lustrous (shiny).
- They are sonorous (ringing sound).
- They have high melting and boiling points.
- They are hard.
- They are malleable and ductile.
- They are good conductors of heat and electricity.

Answer: Option B. -> Low Melting Point
:

When zinc oxide is heated with carbon, it is reduced to metallic zinc. Carbon acts as the reducing agent.

Answer: Option B. -> It involves formation of positive and negative ions.
:
A, B, and D
Atoms try to become stable by attaining inert gas configuration. In this process, they either lose or gain electrons or share electron pairs. Atoms form positive ions and negative ions when they lose and gain electrons respectively.
During the formation of an ionic bond, electron transfer takes place leading to the formation of ions.
A metal and a non-metal combine to form an ionic compound by complete transfer of electrons from a metal to a non-metal.

Answer: Option A. -> True
:
A

In electro-refining process, the impure metal is made the anode and a thin strip of pure metal is made the cathode. A solution of the metal salt is used as an electrolyte.
Upon passing electric current, the copper atoms migrate from the anode towards the cathode and get deposited there.

Answer: Option A. -> gangue
:
A

Impurities found in ores mined from the earth are called gangue. It usually consists of large amounts of soil, sand, stones etc.

Answer: Option C. -> Redox reaction
:
C

During corrosion, metal reacts with oxygen to from oxides. Since oxidation can not occur alone, corrosion is a redox reaction.